CVE-2026-55831
Netty SPDY SETTINGS frame count materializes unbounded settings map
HIGH 7.5EPSS 0.7%
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.
- Affected
- netty
- CVSS v3.1 GITHUB
- 7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.66% chance of exploitation in the next 30 days, 51st percentile
- Published
- 2026-07-20
- Updated
- 2026-07-23
Proof-of-concept exploits (1)
Security advisories
- netty/netty/security/advisories/GHSA-6jqx-86gh-f27w
- netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b