CVE-2026-31675

NameCVE-2026-31675
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/sched: sch_netem: fix out-of-bounds access in packet corruption In netem_enqueue(), the packet corruption logic uses get_random_u32_below(skb_headlen(skb)) to select an index for modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0. Passing 0 to get_random_u32_below() takes the variable-ceil slow path which returns an unconstrained 32-bit random integer. Using this unconstrained value as an offset into skb->data results in an out-of-bounds memory access. Fix this by verifying skb_headlen(skb) is non-zero before attempting to corrupt the linear data area. Fully non-linear packets will silently bypass the corruption logic.
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)
ReferencesDSA-6238-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.251-5vulnerable
bookworm6.1.170-3vulnerable
bookworm (security)6.1.172-1vulnerable
trixie6.12.86-1fixed
trixie (security)6.12.88-1fixed
forky, sid7.0.7-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcetrixie6.12.85-1DSA-6238-1
linuxsource(unstable)6.19.12-1

Notes

https://git.kernel.org/linus/d64cb81dcbd54927515a7f65e5e24affdc73c14b (7.0-rc7)

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