CVE-2026-43503 - net: skbuff: propagate shared-frag marker through frag-transfer helpers

CVE-2026-43503 - net: skbuff: propagate shared-frag marker through frag-transfer helpers

https://cvefeed.io/rssfeed/latest.atom / Sat, 05/23/2026 - 17:25
CVE ID :CVE-2026-43503
Published : May 23, 2026, 11:44 a.m. | 3 hours, 15 minutes ago
Description :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.
Severity: 0.0 | NA
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