Netty HttpServerCodec DoS via HTTP/1.1 pipelining (before 4.2)
CVE-2026-93491 Published on September 18, 2026

Io.netty/netty-codec-http: netty: denial of service via unbounded httpservercodec http/1.1 pipeline queue
A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a single connection and withholding reads. This action causes the methodOverflowQueue to grow without limit, leading to unbounded heap memory consumption and a denial of service due to memory exhaustion.

NVD

Vulnerability Analysis

CVE-2026-93491 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public.

Weakness Type

Allocation of Resources Without Limits or Throttling

The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.


Products Associated with CVE-2026-93491

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Red Hat Amq Broker
 
Red Hat Amq Clients
 
Red Hat Camel Quarkus
 
Red Hat Camel Spring Boot
 
Red Hat Apicurio Registry
 
Red Hat Debezium
 
Red Hat Build Keycloak
 
Red Hat Quarkus
 
Red Hat Jboss Data Grid
 
Red Hat Jboss Fuse
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Single Sign On
 

Affected Versions

Red Hat AMQ Broker 7: Red Hat AMQ Clients: Red Hat build of Apache Camel 4 for Quarkus 3: Red Hat build of Apache Camel for Spring Boot 4: Red Hat build of Apicurio Registry 3: Red Hat build of Debezium 3: Red Hat Build of Keycloak: Red Hat build of Quarkus: Red Hat Data Grid 8: Red Hat Fuse 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat Single Sign-On 7: