CVE-2026-31681

NameCVE-2026-31681
DescriptionIn the Linux kernel, the following vulnerability has been resolved: netfilter: xt_multiport: validate range encoding in checkentry ports_match_v1() treats any non-zero pflags entry as the start of a port range and unconditionally consumes the next ports[] element as the range end. The checkentry path currently validates protocol, flags and count, but it does not validate the range encoding itself. As a result, malformed rules can mark the last slot as a range start or place two range starts back to back, leaving ports_match_v1() to step past the last valid ports[] element while interpreting the rule. Reject malformed multiport v1 rules in checkentry by validating that each range start has a following element and that the following element is not itself marked as another range start.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4664-1, DLA-4665-1, DLA-4671-1, DSA-6238-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.259-1fixed
bookworm, bookworm (security)6.1.176-1fixed
trixie6.12.94-1fixed
trixie (security)6.12.95-1fixed
forky, sid7.1.3-1fixed
linux-6.1 (PTS)bullseye (security)6.1.176-1~deb11u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebullseye5.10.259-1DLA-4664-1
linuxsourcebookworm6.1.176-1DLA-4665-1
linuxsourcetrixie6.12.85-1DSA-6238-1
linuxsource(unstable)6.19.14-1
linux-6.1sourcebullseye6.1.176-1~deb11u1DLA-4671-1

Notes

https://git.kernel.org/linus/ff64c5bfef12461df8450e0f50bb693b5269c720 (7.0)

Search for package or bug name: Reporting problems