CVE-2026-56818 Details
Description
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.
A vulnerability exists in the Netty Redis codec, specifically in the RedisArrayAggregator component, prior to versions 4.1.136.Final and 4.2.16.Final. The issue arises because the aggregator fails to clear retained partial aggregate state when the sibling maxElements limit is exceeded, even though it properly handles such cases when the maxNestedArrayDepth limit is breached. This oversight allows an unauthenticated peer to manipulate the aggregate state and retain pooled buffers, potentially leading to memory management issues.
Users can upgrade to Netty versions 4.1.136.Final or 4.2.16.Final, both of which include the necessary fix. Instructions for upgrading can be found in the Netty documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Aug 8, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/netty/netty/security/advisories/GHSA-p9jm-q85p-7mcp | CISA-ADP | ExploitVendor Advisory |
| https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b | [email protected] | Patch |
| https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 | [email protected] | Patch |
| https://github.com/netty/netty/pull/17065 | [email protected] | Issue TrackingPatch |
| https://github.com/netty/netty/security/advisories/GHSA-p9jm-q85p-7mcp | [email protected] | ExploitVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-401 | Missing Release of Memory after Effective Lifetime | [email protected] |
| CWE-703 | Improper Check or Handling of Exceptional Conditions | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| netty netty | < 4.1.136 >= 4.2.0, < 4.2.16 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 23, 2026 | Initial Analysis | [email protected] |
| Aug 8, 2026 | CVE Modified | CISA-ADP |
| Aug 7, 2026 | New CVE Received | [email protected] |