CVE-2026-55831: Netty SPDY SETTINGS frame count materializes unbounded settings map
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 without an implementation-level count cap. A remote SPDY/3.1 peer can send one syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries, amplifying network input into heap growth and ordered-map insertion work.
References
- github.com/advisories/GHSA-6jqx-86gh-f27w
- github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
- github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
- github.com/netty/netty/releases/tag/netty-4.1.136.Final
- github.com/netty/netty/releases/tag/netty-4.2.16.Final
- github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27w
- nvd.nist.gov/vuln/detail/CVE-2026-55831
Code Behaviors & Features
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