Envoyproxy Envoy

Envoy OAuth2 filter DoS via async token exchange before 1.37.5/1.38.3
CVE-2026-48090 5.9 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.37.0 until 1.37.5 and 1.38.3, the HTTP OAuth2 filter (envoy.filters.http.oauth2) can leave an in-flight async token exchange attached to a downstream stream that has already been torn down. A late AsyncClient completion can still invoke OAuth2Filter methods that use StreamDecoderFilterCallbacks after that objects lifetime has ended, causing undefined behavior, worker crashes (availability loss), and use-after-free / invalid-vptr failures under AddressSanitizer. This is a memory-safety / lifetime issue in the data plane, not a trivial config bug. Remote code execution is not claimed here; the primary demonstrated impact is DoS via crash and UB; any further impact would be deployment- and allocator-dependent. This vulnerability is fixed in 1.37.5 and 1.38.3.

Dangling pointer

Envoy 1.371.38 Crash via HOST_FIRST/SNI_FIRST Log Format
CVE-2026-47220 7.5 - High - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.37.0 until 1.37.5 and 1.38.3, when the %REQUESTED_SERVER_NAME(X:Y)% is used in log format and host related options is specified, like HOST_FIRST, SNI_FIRST, it's possible to crash Envoy when the specified host header is missing in the request headers. This vulnerability is fixed in 1.37.5 and 1.38.3.

NULL Pointer Dereference

Envoy ext_authz UAF vulnerability fixed in 1.36.9/1.37.5/1.38.3
CVE-2026-47205 5.9 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.36.0 until 1.36.9, 1.37.5, and 1.38.3, a Use-After-Free (UAF) vulnerability leading to a sudden segmentation fault exists in Envoy's ext_authz HTTP filter when processing per-route authorization overrides concurrently with rapid downstream client disconnects. During standard request lifecycles, Envoy instantiates the ext_authz filter with a foundational authorization client object (client_). If a matched route dictates a dynamic per-route HTTP or gRPC authorization service override, the filter generates a localized client. In the vulnerable implementation, this transient client aggressively overwrote the default client_ unique pointer by executing client_ = std::move(per_route_client). When a client rapidly establishes and subsequently tears down a stream (such as rapidly refreshing a protected WebSocket endpoint), the downstream triggers the ConnectionManagerImpl::doDeferredStreamDestroy() -> ActiveStream::onResetStream() lifecycle. Envoy immediately sequences Filter::onDestroy() in an attempt to securely abort dispatched asynchronous authorization check transactions via client_->cancel(). By destructing the default client abruptly during initiateCall, a memory lifecycle misalignment occurs within the async client manager. The stream teardown fails to reliably track and cancel the dynamically bound asynchronous authorization tasks, orchestrating a sequence where a late asynchronous callback from the network evaluates against a heavily destroyed ActiveStream validation span, generating a UAF process crash. This vulnerability is fixed in 1.36.9, 1.37.5, and 1.38.3.

Dangling pointer

Envoy PROXY Protocol v2 TLV over-length bug in 1.34-1.38
CVE-2026-47692 4.8 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, PROXY Protocol v2 header generator emits TLVs beyond the maximum length of 65535 bytes, causing a mismatch between bytes written and the length field in the header. This can result in smuggled bytes on the upstream request. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

length manipulation

Envoy Proxy UAF via ext_proc gRPC crash before 1.35.13
CVE-2026-47207 6.5 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, Envoy crashes if an ext_proc server sends a single gRPC message containing multiple, specially crafted ProcessingResponse messages. This can occur when the first response in the batch causes the gRPC stream object to be destroyed, leading to a use-after-free error when Envoy attempts to process subsequent responses in the same gRPC message. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

Dangling pointer

Envoy TCP StatsD Sink Flusher Slice Overflow 1.34-1.38
CVE-2026-48706 5.9 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, a vulnerability exists in Envoy's TCP StatsD sink (TcpStatsdSink), where the thread-local flusher buffer can be overflowed by exceptionally long statistic names (e.g., >16KiB). During formatting, TcpStatsdSink reserves a single contiguous memory slice of 16KiB (FLUSH_SLICE_SIZE_BYTES). If formatting a single metric exceeds the remaining capacity, the flusher initiates a buffer rotation but incorrectly continues to allocate another fixed 16KiB slice. If an attacker can trigger a statistic name longer than 16KiBfor example, by sending an HTTP or gRPC request with an extremely long request path (:path) that is recorded by the grpc_stats filter configured with stats_for_all_methods: truethe flusher will attempt to copy the metric name using memcpy operations beyond the allocated heap buffer boundaries. This leads to a heap write overflow, which can cause immediate denial-of-service (process crash) or potential remote code execution (RCE). This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

Classic Buffer Overflow

Envoy gRPC-Stats NPE Crash 1.26.01.38.3 (direct_response)
CVE-2026-47204 6.5 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.26.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the envoy.filters.http.grpc_stats filter crashes (null pointer dereference / segfault) when a Connect protocol request (Content-Type: application/connect+proto or application/connect+json) hits a direct_response route. A single unauthenticated HTTP request crashes the Envoy process. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

NULL Pointer Dereference

Envoy <1.35.13 Router Filter NPD via 303 Internal Redirect DoS
CVE-2026-47221 5.9 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.18.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the router filter contains a null pointer dereference vulnerability when handling HTTP 303 (See Other) internal redirects for body-less non-GET/HEAD requests. When a POST, PUT, DELETE, or PATCH request without a body is sent to a route configured with internal redirect policy that includes 303 in redirect_response_codes, and the upstream responds with HTTP 303, the redirect handling code attempts to drain a request body buffer that was never allocated. This results in a segmentation fault that crashes the entire Envoy process. When route configured with internal_redirect_policy including 303 in redirect_response_codes and upstream must return HTTP 303 response, an unauthenticated attacker can exploit this to cause complete denial of service, terminating all active connections. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

NULL Pointer Dereference

Envoy H3>HTTP/1 Desync before 1.35.11/1.36.7/1.37.3/1.38.1
CVE-2026-48743 7.5 - High - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer (HEADERS with FIN / headers-only close) but still carries a nonzero Content-Length into a complete upstream HTTP/1 request with unresolved body debt. In an HTTP/1 upstream deployment where the origin replies before reading the declared body and keeps the connection reusable, the beginning of the next Envoy-generated upstream request can be consumed as the first request's body. The remaining bytes are then parsed by the origin as a new HTTP/1 request. This was reproduced as a route-bypass/desync: direct /pwn was denied by Envoy, but the second downstream H3 stream received the response for backend-parsed GET /pwn HTTP/1.1. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

HTTP Request Smuggling

Envoy <1.35.11 UDP DNS Filter Crashes on 255Octet Query
CVE-2026-48497 5.9 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, in cases where UDP DNS filter is configured with local resolution containing a name with the length of 255 octets or remote resolution for a name of 255 octets long can complete successfully, a query with such name will result in abnormal process termination. The abnormal process termination is triggered by an invalid runtime precondition that the query name is strictly less than 255 octets, contradicting DNS specification rfc1035#section-2.3.4 that the name can be 255 or less octets. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Use of Incorrect Operator

Envoy zstd Decompressor OOM DoS (before 1.35.11/1.36.7/1.37.3/1.38.1)
CVE-2026-48044 7.5 - High - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.23.0 until 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability has been identified in Envoy's zstd decompressor implementation (ZstdDecompressorImpl). When zstd decompression is enabled, processing a specially crafted, highly compressed zstd payload can lead to massive memory allocation. An attacker can exploit this to cause severe memory exhaustion, potentially resulting in an Out-Of-Memory (OOM) kill and Denial of Service (DoS) for the Envoy proxy. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Data Amplification

Stack overflow via deep nested JSON in Envoy (pre1.35.11/1.36.7/1.37.3/1.38.1)
CVE-2026-48042 7.5 - High - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, destructor of JSON Object results in stack overflow when deeply O(100K) nested objects are present. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Excessively Deep Nesting

Envoy Proxy <1.35.11 1.36.7 1.37.3 1.38.1: DNS SAN NUL Byte Exploit
CVE-2026-47778 4.4 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Improper Neutralization of Null Byte or NUL Character

Envoy OAuth2 Filter Padding Oracle ( 1.38.1)
CVE-2026-47775 6.8 - Medium - June 26, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, the OAuth2 HTTP filter's encrypt()/decrypt() functions use AES-256-CBC without an authentication tag (no HMAC, no AEAD). The /callback endpoint returns HTTP 302 on successful decryption and HTTP 401 on padding failure, creating a padding oracle. An attacker who obtains the encrypted CodeVerifier cookie can recover the plaintext PKCE code_verifier in ~6,200 requests (~100 seconds), then exchange it with a stolen authorization code to obtain the victim's access token. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Generation of Error Message Containing Sensitive Information

Envoy HTTP/2 OOM DoS (v<1.35.11/1.36.7/1.37.3/1.38.1)
CVE-2026-47774 7.5 - High - June 17, 2026

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability in Envoy's HTTP/2 downstream request processing allows an unauthenticated remote client to trigger excessive memory consumption, potentially resulting in OOM termination of the Envoy process and denial of service. The issue arises from the combination of two behaviors. First, cookie header bytes are not fully accounted for during request header size validation in Envoy. Second, HPACK header block limits in oghttp2/quiche are enforced on encoded bytes without a corresponding limit on total decoded header size. Together, these behaviors allow a malicious client to cause large decoded header allocations while bypassing the intended request header size protections. Versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1 contain a fix. No complete workaround is known short of applying a fix. Possible temporary mitigations include disabling downstream HTTP/2 where operationally feasible; enforcing stricter request header and cookie limits before traffic reaches Envoy; and monitoring Envoy memory usage for abnormal growth under HTTP/2 traffic.

Amplification

Envoy <1.33.0 Query Parameter Handler injection via params.add
CVE-2026-6994 6.3 - Medium - April 25, 2026

A weakness has been identified in Envoy up to 1.33.0. Affected is the function params.add of the file source/extensions/filters/http/header_mutation/header_mutation.cc of the component Query Parameter Handler. This manipulation causes injection. Remote exploitation of the attack is possible. Patch name: f8f4f1e02fdc64ecd4acf2d903208dd7285ad3a4. It is suggested to install a patch to address this issue.

Injection

Envoy Crash via Rate Limit Filter apply_on_stream_done (v<1.37.1)
CVE-2026-26330 5.3 - Medium - March 10, 2026

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, At the rate limit filter, if the response phase limit with apply_on_stream_done in the rate limit configuration is enabled and the response phase limit request fails directly, it may crash Envoy. When both the request phase limit and response phase limit are enabled, the safe gRPC client instance will be re-used for both the request phase request and response phase request. But after the request phase request is done, the inner state of the request phase limit request in gRPC client is not cleaned up. When a second limit request is sent at response phase, and the second limit request fails directly, the previous request's inner state may be accessed and result in crash. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Dangling pointer

Envoy <1.37.1 Zombie Stream Filter Exec UAF
CVE-2026-26311 5.9 - Medium - March 10, 2026

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, a logic vulnerability in Envoy's HTTP connection manager (FilterManager) that allows for Zombie Stream Filter Execution. This issue creates a "Use-After-Free" (UAF) or state-corruption window where filter callbacks are invoked on an HTTP stream that has already been logically reset and cleaned up. The vulnerability resides in source/common/http/filter_manager.cc within the FilterManager::decodeData method. The ActiveStream object remains valid in memory during the deferred deletion window. If a DATA frame arrives on this stream immediately after the reset (e.g., in the same packet processing cycle), the HTTP/2 codec invokes ActiveStream::decodeData, which cascades to FilterManager::decodeData. FilterManager::decodeData fails to check the saw_downstream_reset_ flag. It iterates over the decoder_filters_ list and invokes decodeData() on filters that have already received onDestroy(). This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Dangling pointer

Envoy <1.37.1: Utility::getAddressWithPort IPv6 scoped address crash
CVE-2026-26310 5.9 - Medium - March 10, 2026

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, calling Utility::getAddressWithPort with a scoped IPv6 addresses causes a crash. This utility is called in the data plane from the original_src filter and the dns filter. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Improper Input Validation

Envoy 1.34-1.37.1 Off-By-One Write in JsonEscaper::escapeString
CVE-2026-26309 5.3 - Medium - March 10, 2026

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can corrupt std::string null-termination, causing undefined behavior and potentially leading to crashes or out-of-bounds reads when the resulting string is later treated as a C-string. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

off-by-five

Envoy RBAC Header Logic Flaw (before 1.37.1) via Duplicate Header Injection
CVE-2026-26308 7.5 - High - March 10, 2026

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, the Envoy RBAC (Role-Based Access Control) filter contains a logic vulnerability in how it validates HTTP headers when multiple values are present for the same header name. Instead of validating each header value individually, Envoy concatenates all values into a single comma-separated string. This behavior allows attackers to bypass RBAC policiesspecifically "Deny" rulesby sending duplicate headers, effectively obscuring the malicious value from exact-match mechanisms. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

AuthZ

Envoy v1.33.12-1.36.2 mTLS Cert Matcher Null Byte Bypass
CVE-2025-66220 5 - Medium - December 03, 2025

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoys mTLS certificate matcher for match_typed_subject_alt_names may incorrectly treat certificates containing an embedded null byte (\0) inside an OTHERNAME SAN value as valid matches.

Improper Null Termination

Early CONNECT Data Forwarding in Envoy TCP Proxy (v<=1.36.2)
CVE-2025-64763 3.7 - Low - December 03, 2025

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONNECT tunnel state. By default Envoy continues to allow early CONNECT data to avoid disrupting existing deployments. The envoy.reloadable_features.reject_early_connect_data runtime flag can be set to reject CONNECT requests that send data before a 2xx response when intermediaries upstream from Envoy may reject establishment of a CONNECT tunnel.

Protection Mechanism Failure

Envoy 1.33-1.36.2: JWKS Reentry Bug Causes Crash with Multiple JWTs
CVE-2025-64527 6.5 - Medium - December 03, 2025

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoy crashes when JWT authentication is configured with the remote JWKS fetching, allow_missing_or_failed is enabled, multiple JWT tokens are present in the request headers and the JWKS fetch fails. This is caused by a re-entry bug in the JwksFetcherImpl. When the first token's JWKS fetch fails, onJwksError() callback triggers processing of the second token, which calls fetch() again on the same fetcher object. The original callback's reset() then clears the second fetch's state (receiver_ and request_) which causes a crash when the async HTTP response arrives.

NULL Pointer Dereference

Envoy Lua Filter UAF pre-1.36.2 causes crash
CVE-2025-62504 6.5 - Medium - October 16, 2025

Envoy is an open source edge and service proxy. Envoy versions earlier than 1.36.2, 1.35.6, 1.34.10, and 1.33.12 contain a use-after-free vulnerability in the Lua filter. When a Lua script executing in the response phase rewrites a response body so that its size exceeds the configured per_connection_buffer_limit_bytes (default 1MB), Envoy generates a local reply whose headers override the original response headers, leaving dangling references and causing a crash. This results in denial of service. Updating to versions 1.36.2, 1.35.6, 1.34.10, or 1.33.12 fixes the issue. Increasing per_connection_buffer_limit_bytes (and for HTTP/2 the initial_stream_window_size) or increasing per_request_buffer_limit_bytes / request_body_buffer_limit can reduce the likelihood of triggering the condition but does not correct the underlying memory safety flaw.

Dangling pointer

Envoy TCP ConnPool Crash <1.36.1 via nullptr Buffer Watermark
CVE-2025-62409 - October 16, 2025

Envoy is a cloud-native, open source edge and service proxy. Prior to 1.36.1, 1.35.5, 1.34.9, and 1.33.10, large requests and responses can potentially trigger TCP connection pool crashes due to flow control management in Envoy. It will happen when the connection is closing but upstream data is still coming, resulting in a buffer watermark callback nullptr reference. The vulnerability impacts TCP proxy and HTTP 1 & 2 mixed use cases based on ALPN. This vulnerability is fixed in 1.36.1, 1.35.5, 1.34.9, and 1.33.10.

NULL Pointer Dereference

Envoy URI Template Matcher USDV: '*'-exclusion bypass RBAC before v1.34.1
CVE-2025-46821 - May 07, 2025

Envoy is a cloud-native edge/middle/service proxy. Prior to versions 1.34.1, 1.33.3, 1.32.6, and 1.31.8, Envoy's URI template matcher incorrectly excludes the `*` character from a set of valid characters in the URI path. As a result URI path containing the `*` character will not match a URI template expressions. This can result in bypass of RBAC rules when configured using the `uri_template` permissions. This vulnerability is fixed in Envoy versions v1.34.1, v1.33.3, v1.32.6, v1.31.8. As a workaround, configure additional RBAC permissions using `url_path` with `safe_regex` expression.

Overly Restrictive Regular Expression

Envoy ext_proc filter crash via local reply before 1.33.1/1.32.4/1.31.6/1.30.10
CVE-2025-30157 7.5 - High - March 21, 2025

Envoy is a cloud-native high-performance edge/middle/service proxy. Prior to 1.33.1, 1.32.4, 1.31.6, and 1.30.10, Envoy's ext_proc HTTP filter is at risk of crashing if a local reply is sent to the external server due to the filter's life time issue. A known situation is the failure of a websocket handshake will trigger a local reply leading to the crash of Envoy. This vulnerability is fixed in 1.33.1, 1.32.4, 1.31.6, and 1.30.10.

Improper Cleanup on Thrown Exception

Envoy Proxy Happy Eyeballs Algorithm Crash Vulnerability
CVE-2024-53269 - December 18, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. When additional address are not ip addresses, then the Happy Eyeballs sorting algorithm will crash in data plane. This issue has been addressed in releases 1.32.2, 1.31.4, and 1.30.8. Users are advised to upgrade. Users unable to upgrade may disable Happy Eyeballs and/or change the IP configuration.

Always-Incorrect Control Flow Implementation

Envoy Proxy Null Pointer Dereference Vulnerability in HTTP/1 Server Abort Dispatch
CVE-2024-53270 - December 18, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. In affected versions `sendOverloadError` is going to assume the active request exists when `envoy.load_shed_points.http1_server_abort_dispatch` is configured. If `active_request` is nullptr, only onMessageBeginImpl() is called. However, the `onMessageBeginImpl` will directly return ok status if the stream is already reset leading to the nullptr reference. The downstream reset can actually happen during the H/2 upstream reset. As a result envoy may crash. This issue has been addressed in releases 1.32.3, 1.31.5, 1.30.9, and 1.29.12. Users are advised to upgrade. Users unable to upgrade may disable `http1_server_abort_dispatch` load shed point and/or use a high threshold.

Always-Incorrect Control Flow Implementation

Envoy HTTP/1.1 Non-101 1xx Response Handling Vulnerability
CVE-2024-53271 - December 18, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. In affected versions envoy does not properly handle http 1.1 non-101 1xx responses. This can lead to downstream failures in networked devices. This issue has been addressed in versions 1.31.5 and 1.32.3. Users are advised to upgrade. There are no known workarounds for this issue.

Always-Incorrect Control Flow Implementation

Envoy Header Manipulation via RFC1918 Trust (fixed v1.31.2+)
CVE-2024-45806 6.5 - Medium - September 20, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. A security vulnerability in Envoy allows external clients to manipulate Envoy headers, potentially leading to unauthorized access or other malicious actions within the mesh. This issue arises due to Envoy's default configuration of internal trust boundaries, which considers all RFC1918 private address ranges as internal. The default behavior for handling internal addresses in Envoy has been changed. Previously, RFC1918 IP addresses were automatically considered internal, even if the internal_address_config was empty. The default configuration of Envoy will continue to trust internal addresses while in this release and it will not trust them by default in next release. If you have tooling such as probes on your private network which need to be treated as trusted (e.g. changing arbitrary x-envoy headers) please explicitly include those addresses or CIDR ranges into `internal_address_config`. Successful exploitation could allow attackers to bypass security controls, access sensitive data, or disrupt services within the mesh, like Istio. This issue has been addressed in versions 1.31.2, 1.30.6, 1.29.9, and 1.28.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Insecure Direct Object Reference / IDOR

Envoy 1.31 Crash via oghttp2 HTTP/2 Codec Bug
CVE-2024-45807 7.5 - High - September 20, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy's 1.31 is using `oghttp` as the default HTTP/2 codec, and there are potential bugs around stream management in the codec. To resolve this Envoy will switch off the `oghttp2` by default. The impact of this issue is that envoy will crash. This issue has been addressed in release version 1.31.2. All users are advised to upgrade. There are no known workarounds for this issue.

Always-Incorrect Control Flow Implementation

Envoy - ACCESSLOG Injection via REQUESTED_SERVER_NAME (fixed 1.31.2+)
CVE-2024-45808 6.5 - Medium - September 20, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. A vulnerability has been identified in Envoy that allows malicious attackers to inject unexpected content into access logs. This is achieved by exploiting the lack of validation for the `REQUESTED_SERVER_NAME` field for access loggers. This issue has been addressed in versions 1.31.2, 1.30.6, 1.29.9, and 1.28.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Output Sanitization

Envoy JWT Filter Crash via clear_route_cache (fixed 1.31.2, 1.30.6, 1.29.9)
CVE-2024-45809 7.5 - High - September 20, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. Jwt filter will lead to an Envoy crash when clear route cache with remote JWKs. In the following case: 1. remote JWKs are used, which requires async header processing; 2. clear_route_cache is enabled on the provider; 3. header operations are enabled in JWT filter, e.g. header to claims feature; 4. the routing table is configured in a way that the JWT header operations modify requests to not match any route. When these conditions are met, a crash is triggered in the upstream code due to nullptr reference conversion from route(). The root cause is the ordering of continueDecoding and clearRouteCache. This issue has been addressed in versions 1.31.2, 1.30.6, and 1.29.9. Users are advised to upgrade. There are no known workarounds for this vulnerability.

NULL Pointer Dereference

Envoy 1.31.2+ / 1.30.6 / 1.29.9 / 1.28.7 fix async client crash on sendLocalReply
CVE-2024-45810 6.5 - Medium - September 20, 2024

Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy will crash when the http async client is handling `sendLocalReply` under some circumstance, e.g., websocket upgrade, and requests mirroring. The http async client will crash during the `sendLocalReply()` in http async client, one reason is http async client is duplicating the status code, another one is the destroy of router is called at the destructor of the async stream, while the stream is deferred deleted at first. There will be problems that the stream decoder is destroyed but its reference is called in `router.onDestroy()`, causing segment fault. This will impact ext_authz if the `upgrade` and `connection` header are allowed, and request mirrorring. This issue has been addressed in versions 1.31.2, 1.30.6, 1.29.9, and 1.28.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Buffer Overflow

Envoy Proxy: Authenticated Cmd Exec via Weak Encrypted Upload
CVE-2024-21881 - August 12, 2024

Inadequate Encryption Strength vulnerability allow an authenticated attacker to execute arbitrary OS Commands via encrypted package upload.This issue affects Envoy: 4.x and 5.x

Envoy Memory Reuse in Route Hash Policy Cookie Attribute (1.30.3)
CVE-2024-39305 - July 01, 2024

Envoy is a cloud-native, open source edge and service proxy. Prior to versions 1.30.4, 1.29.7, 1.28.5, and 1.27.7. Envoy references already freed memory when route hash policy is configured with cookie attributes. Note that this vulnerability has been fixed in the open as the effect would be immediately apparent if it was configured. Memory allocated for holding attribute values is freed after configuration was parsed. During request processing Envoy will attempt to copy content of de-allocated memory into request cookie header. This can lead to arbitrary content of Envoy's memory to be sent to the upstream service or abnormal process termination. This vulnerability is fixed in Envoy versions v1.30.4, v1.29.7, v1.28.5, and v1.27.7. As a workaround, do not use cookie attributes in route action hash policy.

Envoy OOM via Mirror Response Unbounded Buffer Abuse
CVE-2024-34364 6.5 - Medium - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. Envoy exposed an out-of-memory (OOM) vector from the mirror response, since async HTTP client will buffer the response with an unbounded buffer.

Memory Corruption

Envoy request smuggling via 200/101 upgrade mismatch
CVE-2024-23326 8.2 - High - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. A theoretical request smuggling vulnerability exists through Envoy if a server can be tricked into adding an upgrade header into a response. Per RFC https://www.rfc-editor.org/rfc/rfc7230#section-6.7 a server sends 101 when switching protocols. Envoy incorrectly accepts a 200 response from a server when requesting a protocol upgrade, but 200 does not indicate protocol switch. This opens up the possibility of request smuggling through Envoy if the server can be tricked into adding the upgrade header to the response.

HTTP Request Smuggling

Envoy UAF via QUICHE in QuicServerStream (CVE-2024-32974)
CVE-2024-32974 7.5 - High - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. A crash was observed in `EnvoyQuicServerStream::OnInitialHeadersComplete()` with following call stack. It is a use-after-free caused by QUICHE continuing push request headers after `StopReading()` being called on the stream. As after `StopReading()`, the HCM's `ActiveStream` might have already be destroyed and any up calls from QUICHE could potentially cause use after free.

Dangling pointer

Envoy Proxy Crash via Integer Underflow in QuicStreamSequencerBuffer
CVE-2024-32975 7.5 - High - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. There is a crash at `QuicheDataReader::PeekVarInt62Length()`. It is caused by integer underflow in the `QuicStreamSequencerBuffer::PeekRegion()` implementation.

Integer underflow

EnvoyProxy: Endless Loop in Brotli Decompression Filter
CVE-2024-32976 7.5 - High - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. Envoyproxy with a Brotli filter can get into an endless loop during decompression of Brotli data with extra input.

Infinite Loop

Envoy HCM Use-After-Free Crash via QUIC Reset
CVE-2024-34362 5.9 - Medium - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. There is a use-after-free in `HttpConnectionManager` (HCM) with `EnvoyQuicServerStream` that can crash Envoy. An attacker can exploit this vulnerability by sending a request without `FIN`, then a `RESET_STREAM` frame, and then after receiving the response, closing the connection.

Dangling pointer

Envoy JSON Exception Crash CVE-2024-34363
CVE-2024-34363 7.5 - High - June 04, 2024

Envoy is a cloud-native, open source edge and service proxy. Due to how Envoy invoked the nlohmann JSON library, the library could throw an uncaught exception from downstream data if incomplete UTF-8 strings were serialized. The uncaught exception would cause Envoy to crash.

Envoy HTTP/2 CONTINUATION Flood CVE-2024-30255 CPU Exhaustion before 1.29.3
CVE-2024-30255 5.3 - Medium - April 04, 2024

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

Detection of Error Condition Without Action

Envoy 1.29.01.29.1 HTTP/2 codec CONTINUATION Flood DoS Vulnerability
CVE-2024-27919 7.5 - High - April 04, 2024

Envoy is a cloud-native, open-source edge and service proxy. In versions 1.29.0 and 1.29.1, theEnvoy HTTP/2 protocol stack is vulnerable to the flood of CONTINUATION frames. Envoy's HTTP/2 codec does not reset a request when header map limits have been exceeded. This allows an attacker to send an sequence of CONTINUATION frames without the END_HEADERS bit set causing unlimited memory consumption. This can lead to denial of service through memory exhaustion. Users should upgrade to versions 1.29.2 to mitigate the effects of the CONTINUATION flood. Note that this vulnerability is a regression in Envoy version 1.29.0 and 1.29.1 only. As a workaround, downgrade to version 1.28.1 or earlier or disable HTTP/2 protocol for downstream connections.

Detection of Error Condition Without Action

Envoy Crash on Timeout Misconfig (before 1.29.1)
CVE-2024-23322 7.5 - High - February 09, 2024

Envoy is a high-performance edge/middle/service proxy. Envoy will crash when certain timeouts happen within the same interval. The crash occurs when the following are true: 1. hedge_on_per_try_timeout is enabled, 2. per_try_idle_timeout is enabled (it can only be done in configuration), 3. per-try-timeout is enabled, either through headers or configuration and its value is equal, or within the backoff interval of the per_try_idle_timeout. This issue has been addressed in released 1.29.1, 1.28.1, 1.27.3, and 1.26.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Dangling pointer

Envoy PPv2 Header Segfault CVE-2024-23327 (before1.29.1)
CVE-2024-23327 7.5 - High - February 09, 2024

Envoy is a high-performance edge/middle/service proxy. When PPv2 is enabled both on a listener and subsequent cluster, the Envoy instance will segfault when attempting to craft the upstream PPv2 header. This occurs when the downstream request has a command type of LOCAL and does not have the protocol block. This issue has been addressed in releases 1.29.1, 1.28.1, 1.27.3, and 1.26.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

NULL Pointer Dereference

Envoy Proxy Protocol Crash on IPv6 via IPv4 (before 1.29.1)
CVE-2024-23325 7.5 - High - February 09, 2024

Envoy is a high-performance edge/middle/service proxy. Envoy crashes in Proxy protocol when using an address type that isnt supported by the OS. Envoy is susceptible to crashing on a host with IPv6 disabled and a listener config with proxy protocol enabled when it receives a request where the client presents its IPv6 address. It is valid for a client to present its IPv6 address to a target server even though the whole chain is connected via IPv4. This issue has been addressed in released 1.29.1, 1.28.1, 1.27.3, and 1.26.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Improper Handling of Exceptional Conditions