CVE-2026-55831 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-55831HIGH

Netty SPDY SETTINGS frame count materializes unbounded settings map

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  N  N  H    7.5   .0042   35.5     —

AFFECTED
  Product  Versions                          Fixed
  netty    >= 4.2.0.Final, < 4.2.16.Final –  —

TIMELINE
  Jun 17  Reserved by GitHub_M
  Jul 20  Published (CNA: GitHub_M)
  Jul 21  EXPLOIT PUBLISHED — CVE-2026-55831 (netty). Public exploit reference added.
  Jul 23  EXPLOIT PUBLISHED — CVE-2026-55831 (netty). Public exploit reference added.

CWE-400, CWE-770 · CNA: GitHub_M · CVSS v3.1 · 5 references · NVD status: Modified

Description

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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
June 17, 2026	Reserved	Reserved by GitHub_M
July 20, 2026	Published	Published (CNA: GitHub_M)
July 21, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55831 (netty). Public exploit reference added.
July 23, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55831 (netty). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
netty	netty	—	>= 4.2.0.Final, < 4.2.16.Final	—

Weaknesses

CWE-400 · CWE-770

References (5)

https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b [Patch]
https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 [Patch]
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final [Release Notes]
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final [Release Notes]
https://github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27w [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-55831 at cve.org

Vendors: netty

Weaknesses: CWE-400 · CWE-770

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-55831 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.