CVE catalog

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

[CVE catalog]

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Jul 14, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.66% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	netty	sid	`1:4.1.48-16`	vulnerable
Debian	netty	forky	`1:4.1.48-16`	vulnerable
Debian	netty	trixie	`1:4.1.48-10+deb13u1`	vulnerable
Debian	netty	trixie-security	`1:4.1.48-10+deb13u1`	vulnerable
Debian	netty	bookworm	`1:4.1.48-7+deb12u2`	vulnerable
Debian	netty	bookworm-security	`1:4.1.48-7+deb12u2`	vulnerable
Cpe	netty	Not reported	Not reported	vulnerable
Maven	io.netty:netty-codec-http	Not reported	`4.2.16.Final`	fixed
Maven	io.netty:netty-codec-http	Not reported	`4.1.136.Final`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	netty	source	sid	`(unfixed)`	not yet assigned	Not reported	[1142680]
Debian	netty	source	forky	`(unfixed)`	not yet assigned	Not reported	[1142680]
Debian	netty	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1142680]
Debian	netty	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1142680]
Maven	io.netty:netty-codec-http	maven	Not reported	`4.2.16.Final`	Not reported	Not reported	Not reported
Maven	io.netty:netty-codec-http	maven	Not reported	`4.1.136.Final`	Not reported	Not reported	Not reported

[Debian bug #1142680]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libnetty-java]Affected
Source package: [netty]
Details (4)
- 1:4.1.48-7+deb12u2 · all · bookworm
  Affected
  nvd · netty · debian · bookworm; nvd · netty · debian · 12
- 1:4.1.48-7+deb12u2 · all · bookworm
  Affected
  nvd · netty · debian · bookworm; nvd · netty · debian · 12
- 1:4.1.48-7+deb12u2 · all · bookworm-security
  Affected
  nvd · netty · debian · bookworm; nvd · netty · debian · 12
- 1:4.1.48-7+deb12u2 · all · bookworm-security
  Affected
  nvd · netty · debian · bookworm; nvd · netty · debian · 12

[Debian 13 (Trixie)]

[libnetty-java]Affected
Source package: [netty]
Details (4)
- 1:4.1.48-10+deb13u1 · all · trixie
  Affected
  nvd · netty · debian · 13
- 1:4.1.48-10+deb13u1 · all · trixie
  Affected
  nvd · netty · debian · 13
- 1:4.1.48-10+deb13u1 · all · trixie-security
  Affected
  nvd · netty · debian · 13
- 1:4.1.48-10+deb13u1 · all · trixie-security
  Affected
  nvd · netty · debian · 13

Observed: Oct 27, 2026, 7:12:54 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]