CVE-2026-55831

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

• CWE-400
• CWE-770

• https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003bPatch
• https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6Patch
• https://github.com/netty/netty/releases/tag/netty-4.1.136.FinalRelease Notes
• https://github.com/netty/netty/releases/tag/netty-4.2.16.FinalRelease Notes
• https://github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27wExploit, Vendor Advisory
• https://github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27wExploit, Vendor Advisory

Published

Jul 21, 2026

Last Modified

Jul 23, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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