Apache HTTP Server

Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server

CVE-2025-53020 - July 10, 2025

Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63. Users are recommended to upgrade to version 2.4.64, which fixes the issue.

Memory Leak

In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack

CVE-2025-49812 - July 10, 2025

In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade. Only configurations using "SSLEngine optional" to enable TLS upgrades are affected. Users are recommended to upgrade to version 2.4.64, which removes support for TLS upgrade.

authentification

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63

CVE-2025-49630 - July 10, 2025

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

assertion failure

In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.63

CVE-2025-23048 - July 10, 2025

In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.63, an access control bypass by trusted clients is possible using TLS 1.3 session resumption. Configurations are affected when mod_ssl is configured for multiple virtual hosts, with each restricted to a different set of trusted client certificates (for example with a different SSLCACertificateFile/Path setting). In such a case, a client trusted to access one virtual host may be able to access another virtual host, if SSLStrictSNIVHostCheck is not enabled in either virtual host.

Authorization

Insufficient escaping of user-supplied data in mod_ssl in Apache HTTP Server 2.4.63 and earlier

CVE-2024-47252 - July 10, 2025

Insufficient escaping of user-supplied data in mod_ssl in Apache HTTP Server 2.4.63 and earlier allows an untrusted SSL/TLS client to insert escape characters into log files in some configurations. In a logging configuration where CustomLog is used with "%{varname}x" or "%{varname}c" to log variables provided by mod_ssl such as SSL_TLS_SNI, no escaping is performed by either mod_log_config or mod_ssl and unsanitized data provided by the client may appear in log files.

Improper Neutralization of Escape, Meta, or Control Sequences

Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via  mod_rewrite or apache expressions

CVE-2024-43394 - July 10, 2025

Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via  mod_rewrite or apache expressions that pass unvalidated request input. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.63. Note:  The Apache HTTP Server Project will be setting a higher bar for accepting vulnerability reports regarding SSRF via UNC paths. The server offers limited protection against administrators directing the server to open UNC paths. Windows servers should limit the hosts they will connect over via SMB based on the nature of NTLM authentication.

SSRF

SSRF in Apache HTTP Server with mod_proxy loaded allows an attacker to send outbound proxy requests to a URL controlled by the attacker

CVE-2024-43204 - July 10, 2025

SSRF in Apache HTTP Server with mod_proxy loaded allows an attacker to send outbound proxy requests to a URL controlled by the attacker.  Requires an unlikely configuration where mod_headers is configured to modify the Content-Type request or response header with a value provided in the HTTP request. Users are recommended to upgrade to version 2.4.64 which fixes this issue.

SSRF

HTTP response splitting in the core of Apache HTTP Server

CVE-2024-42516 - July 10, 2025

HTTP response splitting in the core of Apache HTTP Server allows an attacker who can manipulate the Content-Type response headers of applications hosted or proxied by the server can split the HTTP response. This vulnerability was described as CVE-2023-38709 but the patch included in Apache HTTP Server 2.4.59 did not address the issue. Users are recommended to upgrade to version 2.4.64, which fixes this issue.

Improper Input Validation

A flaw was found in the mod_auth_openidc module for Apache httpd

CVE-2025-3891 7.5 - High - April 29, 2025

A flaw was found in the mod_auth_openidc module for Apache httpd. This flaw allows a remote, unauthenticated attacker to trigger a denial of service by sending an empty POST request when the OIDCPreservePost directive is enabled. The server crashes consistently, affecting availability.

Uncaught Exception

D-Link DAP-2310 Hardware A Firmware 1.16RC028 allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the ATP binary

CVE-2024-45623 - September 02, 2024

D-Link DAP-2310 Hardware A Firmware 1.16RC028 allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the ATP binary that handles PHP HTTP GET requests for the Apache HTTP Server (httpd). NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

SSRF in Apache HTTP Server on Windows with mod_rewrite in server/vhost context

CVE-2024-40898 7.5 - High - July 18, 2024

SSRF in Apache HTTP Server on Windows with mod_rewrite in server/vhost context, allows to potentially leak NTML hashes to a malicious server via SSRF and malicious requests. Users are recommended to upgrade to version 2.4.62 which fixes this issue. 

SSRF

A partial fix for  CVE-2024-39884 in the core of Apache HTTP Server 2.4.61 ignores some use of the legacy content-type based configuration of handlers

CVE-2024-40725 5.3 - Medium - July 18, 2024

A partial fix for  CVE-2024-39884 in the core of Apache HTTP Server 2.4.61 ignores some use of the legacy content-type based configuration of handlers. "AddType" and similar configuration, under some circumstances where files are requested indirectly, result in source code disclosure of local content. For example, PHP scripts may be served instead of interpreted. Users are recommended to upgrade to version 2.4.62, which fixes this issue.

Exposure of Resource to Wrong Sphere

A regression in the core of Apache HTTP Server 2.4.60 ignores some use of the legacy content-type based configuration of handlers

CVE-2024-39884 - July 04, 2024

A regression in the core of Apache HTTP Server 2.4.60 ignores some use of the legacy content-type based configuration of handlers.   "AddType" and similar configuration, under some circumstances where files are requested indirectly, result in source code disclosure of local content. For example, PHP scripts may be served instead of interpreted. Users are recommended to upgrade to version 2.4.61, which fixes this issue.

null pointer dereference in mod_proxy in Apache HTTP Server 2.4.59 and earlier

CVE-2024-38477 7.5 - High - July 01, 2024

null pointer dereference in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows an attacker to crash the server via a malicious request. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

NULL Pointer Dereference

Vulnerability in core of Apache HTTP Server 2.4.59 and earlier are vulnerably to information disclosure, SSRF or local script execution

CVE-2024-38476 9.8 - Critical - July 01, 2024

Vulnerability in core of Apache HTTP Server 2.4.59 and earlier are vulnerably to information disclosure, SSRF or local script execution via backend applications whose response headers are malicious or exploitable. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

Inclusion of Functionality from Untrusted Control Sphere

Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations

CVE-2024-38475 - July 01, 2024

Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure. Substitutions in server context that use a backreferences or variables as the first segment of the substitution are affected.  Some unsafe RewiteRules will be broken by this change and the rewrite flag "UnsafePrefixStat" can be used to opt back in once ensuring the substitution is appropriately constrained.

Output Sanitization

Substitution encoding issue in mod_rewrite in Apache HTTP Server 2.4.59 and earlier

CVE-2024-38474 9.8 - Critical - July 01, 2024

Substitution encoding issue in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows attacker to execute scripts in directories permitted by the configuration but not directly reachable by any URL or source disclosure of scripts meant to only to be executed as CGI. Users are recommended to upgrade to version 2.4.60, which fixes this issue. Some RewriteRules that capture and substitute unsafely will now fail unless rewrite flag "UnsafeAllow3F" is specified.

Output Sanitization

Potential SSRF in mod_rewrite in Apache HTTP Server 2.4.59 and earlier

CVE-2024-39573 - July 01, 2024

Potential SSRF in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to cause unsafe RewriteRules to unexpectedly setup URL's to be handled by mod_proxy. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

Improper Input Validation

Encoding problem in mod_proxy in Apache HTTP Server 2.4.59 and earlier

CVE-2024-38473 - July 01, 2024

Encoding problem in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows request URLs with incorrect encoding to be sent to backend services, potentially bypassing authentication via crafted requests. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

Output Sanitization

SSRF in Apache HTTP Server on Windows

CVE-2024-38472 - July 01, 2024

SSRF in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via SSRF and malicious requests or content Users are recommended to upgrade to version 2.4.60 which fixes this issue.  Note: Existing configurations that access UNC paths will have to configure new directive "UNCList" to allow access during request processing.

Serving WebSocket protocol upgrades over a HTTP/2 connection could result in a Null Pointer dereference

CVE-2024-36387 - July 01, 2024

Serving WebSocket protocol upgrades over a HTTP/2 connection could result in a Null Pointer dereference, leading to a crash of the server process, degrading performance.

NULL Pointer Dereference

HTTP Response splitting in multiple modules in Apache HTTP Server allows an attacker

CVE-2024-24795 - April 04, 2024

HTTP Response splitting in multiple modules in Apache HTTP Server allows an attacker that can inject malicious response headers into backend applications to cause an HTTP desynchronization attack. Users are recommended to upgrade to version 2.4.59, which fixes this issue.

Faulty input validation in the core of Apache allows malicious or exploitable backend/content generators to split HTTP responses

CVE-2023-38709 - April 04, 2024

Faulty input validation in the core of Apache allows malicious or exploitable backend/content generators to split HTTP responses. This issue affects Apache HTTP Server: through 2.4.58.

HTTP/2 incoming headers exceeding the limit are temporarily buffered in nghttp2 in order to generate an informative HTTP 413 response

CVE-2024-27316 7.5 - High - April 04, 2024

HTTP/2 incoming headers exceeding the limit are temporarily buffered in nghttp2 in order to generate an informative HTTP 413 response. If a client does not stop sending headers, this leads to memory exhaustion.

Allocation of Resources Without Limits or Throttling

The Elementor Website Builder Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting

CVE-2024-1521 5.4 - Medium - March 27, 2024

The Elementor Website Builder Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via an SVGZ file uploaded via the Form widget in all versions up to, and including, 3.20.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. NOTE: This vulnerability is only exploitable on web servers running NGINX. It is not exploitable on web servers running Apache HTTP Server.

XSS

Request smuggling vulnerability in HTTP server in Apache bRPC 0.9.5~1.7.0 on all platforms allows attacker to smuggle request

CVE-2024-23452 7.5 - High - February 08, 2024

Request smuggling vulnerability in HTTP server in Apache bRPC 0.9.5~1.7.0 on all platforms allows attacker to smuggle request. Vulnerability Cause Description: The http_parser does not comply with the RFC-7230 HTTP 1.1 specification. Attack scenario: If a message is received with both a Transfer-Encoding and a Content-Length header field, such a message might indicate an attempt to perform request smuggling or response splitting. One particular attack scenario is that a bRPC made http server on the backend receiving requests in one persistent connection from frontend server that uses TE to parse request with the logic that 'chunk' is contained in the TE field. in that case an attacker can smuggle a request into the connection to the backend server.  Solution: You can choose one solution from below: 1. Upgrade bRPC to version 1.8.0, which fixes this issue. Download link: https://github.com/apache/brpc/releases/tag/1.8.0 2. Apply this patch:  https://github.com/apache/brpc/pull/2518

HTTP Request Smuggling

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of

CVE-2023-43622 7.5 - High - October 23, 2023

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Resource Exhaustion

When a HTTP/2 stream was reset (RST frame) by a client

CVE-2023-45802 5.9 - Medium - October 23, 2023

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that. This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Improper Resource Shutdown or Release

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

CVE-2023-31122 7.5 - High - October 23, 2023

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

Out-of-bounds Read

The HTTP/2 protocol

CVE-2023-44487 7.5 - High - October 10, 2023

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

Resource Exhaustion

In LemonLDAP::NG (aka lemonldap-ng) before 2.0.7

CVE-2019-19791 9.8 - Critical - May 29, 2023

In LemonLDAP::NG (aka lemonldap-ng) before 2.0.7, the default Apache HTTP Server configuration does not properly restrict access to SOAP/REST endpoints (when some LemonLDAP::NG setup options are used). For example, an attacker can insert index.fcgi/index.fcgi into a URL to bypass a Require directive.

mod_auth_openidc is an authentication and authorization module for the Apache 2.x HTTP server

CVE-2023-28625 7.5 - High - April 03, 2023

mod_auth_openidc is an authentication and authorization module for the Apache 2.x HTTP server that implements the OpenID Connect Relying Party functionality. In versions 2.0.0 through 2.4.13.1, when `OIDCStripCookies` is set and a crafted cookie supplied, a NULL pointer dereference would occur, resulting in a segmentation fault. This could be used in a Denial-of-Service attack and thus presents an availability risk. Version 2.4.13.2 contains a patch for this issue. As a workaround, avoid using `OIDCStripCookies`.

NULL Pointer Dereference

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack

CVE-2023-25690 9.8 - Critical - March 07, 2023

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like: RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.

HTTP Request Smuggling

HTTP Response Smuggling vulnerability in Apache HTTP Server via mod_proxy_uwsgi

CVE-2023-27522 7.5 - High - March 07, 2023

HTTP Response Smuggling vulnerability in Apache HTTP Server via mod_proxy_uwsgi. This issue affects Apache HTTP Server: from 2.4.30 through 2.4.55. Special characters in the origin response header can truncate/split the response forwarded to the client.

HTTP Request Smuggling

Prior to Apache HTTP Server 2.4.55, a malicious backend

CVE-2022-37436 5.3 - Medium - January 17, 2023

Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.

HTTP Response Splitting

A carefully crafted If: request header

CVE-2006-20001 7.5 - High - January 17, 2023

A carefully crafted If: request header can cause a memory read, or write of a single zero byte, in a pool (heap) memory location beyond the header value sent. This could cause the process to crash. This issue affects Apache HTTP Server 2.4.54 and earlier.

Memory Corruption

Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server

CVE-2022-36760 9 - Critical - January 17, 2023

Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server allows an attacker to smuggle requests to the AJP server it forwards requests to. This issue affects Apache HTTP Server Apache HTTP Server 2.4 version 2.4.54 and prior versions.

HTTP Request Smuggling

If Apache HTTP Server 2.4.53 is configured to do transformations with mod_sed in contexts where the input to mod_sed may be very large

CVE-2022-30522 7.5 - High - June 09, 2022

If Apache HTTP Server 2.4.53 is configured to do transformations with mod_sed in contexts where the input to mod_sed may be very large, mod_sed may make excessively large memory allocations and trigger an abort.

Allocation of Resources Without Limits or Throttling

In Apache HTTP Server 2.4.53 and earlier, a malicious request to a lua script

CVE-2022-29404 7.5 - High - June 09, 2022

In Apache HTTP Server 2.4.53 and earlier, a malicious request to a lua script that calls r:parsebody(0) may cause a denial of service due to no default limit on possible input size.

Allocation of Resources Without Limits or Throttling

Apache HTTP Server 2.4.53 and earlier may crash or disclose information due to a read beyond bounds in ap_strcmp_match() when provided with an extremely large input buffer

CVE-2022-28615 9.1 - Critical - June 09, 2022

Apache HTTP Server 2.4.53 and earlier may crash or disclose information due to a read beyond bounds in ap_strcmp_match() when provided with an extremely large input buffer. While no code distributed with the server can be coerced into such a call, third-party modules or lua scripts that use ap_strcmp_match() may hypothetically be affected.

Integer Overflow or Wraparound

The ap_rwrite() function in Apache HTTP Server 2.4.53 and earlier may read unintended memory if an attacker

CVE-2022-28614 5.3 - Medium - June 09, 2022

The ap_rwrite() function in Apache HTTP Server 2.4.53 and earlier may read unintended memory if an attacker can cause the server to reflect very large input using ap_rwrite() or ap_rputs(), such as with mod_luas r:puts() function. Modules compiled and distributed separately from Apache HTTP Server that use the 'ap_rputs' function and may pass it a very large (INT_MAX or larger) string must be compiled against current headers to resolve the issue.

Integer Overflow or Wraparound

Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server

CVE-2022-26377 7.5 - High - June 09, 2022

Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server allows an attacker to smuggle requests to the AJP server it forwards requests to. This issue affects Apache HTTP Server Apache HTTP Server 2.4 version 2.4.53 and prior versions.

HTTP Request Smuggling

Apache HTTP Server 2.4.53 and earlier may not send the X-Forwarded-* headers to the origin server based on client side Connection header hop-by-hop mechanism

CVE-2022-31813 9.8 - Critical - June 09, 2022

Apache HTTP Server 2.4.53 and earlier may not send the X-Forwarded-* headers to the origin server based on client side Connection header hop-by-hop mechanism. This may be used to bypass IP based authentication on the origin server/application.

Insufficient Verification of Data Authenticity

Apache HTTP Server 2.4.53 and earlier may return lengths to applications calling r:wsread()

CVE-2022-30556 7.5 - High - June 09, 2022

Apache HTTP Server 2.4.53 and earlier may return lengths to applications calling r:wsread() that point past the end of the storage allocated for the buffer.

Apache HTTP Server 2.4.53 and earlier on Windows may read beyond bounds when configured to process requests with the mod_isapi module.

CVE-2022-28330 5.3 - Medium - June 09, 2022

Apache HTTP Server 2.4.53 and earlier on Windows may read beyond bounds when configured to process requests with the mod_isapi module.

Out-of-bounds Read

If LimitXMLRequestBody is set to

CVE-2022-22721 9.1 - Critical - March 14, 2022

If LimitXMLRequestBody is set to allow request bodies larger than 350MB (defaults to 1M) on 32 bit systems an integer overflow happens which later causes out of bounds writes. This issue affects Apache HTTP Server 2.4.52 and earlier.

Integer Overflow or Wraparound

Out-of-bounds Write vulnerability in mod_sed of Apache HTTP Server

CVE-2022-23943 9.8 - Critical - March 14, 2022

Out-of-bounds Write vulnerability in mod_sed of Apache HTTP Server allows an attacker to overwrite heap memory with possibly attacker provided data. This issue affects Apache HTTP Server 2.4 version 2.4.52 and prior versions.

Memory Corruption

A carefully crafted request body can cause a read to a random memory area which could cause the process to crash

CVE-2022-22719 7.5 - High - March 14, 2022

A carefully crafted request body can cause a read to a random memory area which could cause the process to crash. This issue affects Apache HTTP Server 2.4.52 and earlier.

Improper Initialization

Apache HTTP Server 2.4.52 and earlier fails to close inbound connection when errors are encountered discarding the request body

CVE-2022-22720 9.8 - Critical - March 14, 2022

Apache HTTP Server 2.4.52 and earlier fails to close inbound connection when errors are encountered discarding the request body, exposing the server to HTTP Request Smuggling

HTTP Request Smuggling

A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts)

CVE-2021-44790 9.8 - Critical - December 20, 2021

A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts). The Apache httpd team is not aware of an exploit for the vulnerabilty though it might be possible to craft one. This issue affects Apache HTTP Server 2.4.51 and earlier.

Memory Corruption