Netty 4.x HttpContentDecompressor OOM DoS via br, zstd, snappy bypass
CVE-2026-42587 Published on May 13, 2026

Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

NVD

Vulnerability Analysis

CVE-2026-42587 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. An automatable proof of concept (POC) exploit exists. 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

Weakness Types

What is a Resource Exhaustion Vulnerability?

The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.

CVE-2026-42587 has been classified to as a Resource Exhaustion vulnerability or weakness.

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-2026-42587

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-42587 are published in these products:

Netty
 
Red Hat Cryostat
 
Red Hat Openshift Devspaces
 
Red Hat Quarkus
 
Red Hat Serverless
 
Red Hat Amq Broker
 
Red Hat Amq Clients
 
Red Hat Camel Spring Boot
 
Red Hat Service Registry
 
Red Hat Apicurio Registry
 
Red Hat Debezium
 
Red Hat Build Keycloak
 
Red Hat Optaplanner
 
Red Hat Jboss Data Grid
 
Red Hat Jboss Fuse
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Jbosseapxp
 
Red Hat Openshift Ai
 
Red Hat Jboss Enterprise Bpms Platform
 
Red Hat Single Sign On
 
Red Hat Amq Streams
 
Red Hat Camel Quarkus
 
Red Hat Enterprise Linux Ai
 
Red Hat Satellite
 
Red Hat Kafka
 
Red Hat Apache Camel Spring Boot
 

Affected Versions

netty: io.netty netty-codec-http: io.netty netty-codec-http2: Red Hat Cryostat 4 on RHEL 9: Red Hat Cryostat 4 on RHEL 9: Red Hat Cryostat 4 on RHEL 9: Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16: Red Hat build of Quarkus 3.27.4: Red Hat build of Quarkus 3.33.2: Red Hat Streams for Apache Kafka 2.9.4: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.29: Red Hat Cryostat 4: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat AMQ Broker 7: 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 4 for Quarkus 3: Red Hat build of Apicurio Registry 2: Red Hat build of Apicurio Registry 2: Red Hat build of Apicurio Registry 3: Red Hat build of Apicurio Registry 3: Red Hat build of Debezium 3: Red Hat build of Debezium 3: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat build of OptaPlanner 8: Red Hat build of OptaPlanner 8: Red Hat Data Grid 8: Red Hat Data Grid 8: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Fuse 7: Red Hat Fuse 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat Process Automation 7: Red Hat Process Automation 7: Red Hat Satellite 6: Red Hat Satellite 6: Red Hat Single Sign-On 7: Red Hat Single Sign-On 7: Red Hat streams for Apache Kafka 2: Red Hat streams for Apache Kafka 3: Red Hat streams for Apache Kafka 3:

Exploit Probability

EPSS
0.53%
Percentile
40.27%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.