Netty is an asynchronous, event-driven network application framework

Overview

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, the RedisArrayAggregator Redis codec clears retained partial aggregate state when the maxNestedArrayDepth limit is exceeded, but it does not clear the same state when the sibling maxElements limit is exceeded. A peer can start a valid RESP array, send a bulk string child, then send a nested array header longer than the configured maxElements. Netty throws a decoder exception in decodeRedisArrayHeader, but the existing partial aggregate remains retained in the handler. If the application leaves the channel alive after the exception, later messages are still consumed into the pre-error aggregate, allowing an unauthenticated peer to keep attacker-controlled aggregate state alive across a security-limit exception and pin retained pooled buffers. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Affected

• netty < 4.1.136
• netty >= 4.2.0, < 4.2.16

Remediation

Upgrade past the affected range:

• netty 4.2.16

Package advisory (CVE-2026-56818)

Affected packages:

• io.netty:netty-codec-redis < 4.1.136.Final
• io.netty:netty-codec-redis >= 4.2.0-Final, < 4.2.16.Final

Patched in:

• io.netty:netty-codec-redis 4.1.136.Final
• io.netty:netty-codec-redis 4.2.16.Final

Source: https://github.com/advisories/GHSA-p9jm-q85p-7mcp

Vendor advisories

• Red Hat VEX · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7 · no fix planned: Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7, Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, … · updated 2026-09-23 · vex