ALT-PU-2026-8612-2

Package update kernel-image-6.18 in branch sisyphus

Version6.18.34-alt1

Published2026-06-02

Max severityHIGH

Severity:

Closed issues (2)

HIGH7.8

Уязвимость функции skb_try_coalesce() ядра операционной системы Linux, позволяющая нарушителю повысить свои привилегии

Published: 2026-05-13Modified: 2026-05-31

CVSS 3.xHIGH 7.8

CVSS:3.x/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 2.0MEDIUM 6.8

CVSS:2.0/AV:L/AC:L/Au:S/C:C/I:C/A:C

References

HIGH7.8

In 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.

Published: 2026-05-23Modified: 2026-05-30

CVSS 3.xHIGH 7.8

CVSS:3.x/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References