CVE-2026-46300

NameCVE-2026-46300
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.
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-4606-1, DLA-4607-1, DSA-6295-1, DSA-6306-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.257-1fixed
bookworm6.1.170-3vulnerable
bookworm (security)6.1.174-1fixed
trixie6.12.86-1vulnerable
trixie (security)6.12.90-2fixed
forky, sid7.0.10-1fixed
linux-6.1 (PTS)bullseye (security)6.1.174-1~deb11u1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebullseye5.10.257-1DLA-4606-1
linuxsourcebookworm6.1.174-1DSA-6306-1
linuxsourcetrixie6.12.90-1DSA-6295-1
linuxsource(unstable)7.0.9-1
linux-6.1sourcebullseye6.1.174-1~deb11u1DLA-4607-1

Notes

https://github.com/v12-security/pocs/tree/main/fragnesia
https://lore.kernel.org/all/20260513041635.1289541-1-vakzz@zellic.io/
https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/
https://git.kernel.org/linus/f84eca5817390257cef78013d0112481c503b4a3

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