High · published May 23, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 3.9, ≤ 5.10.257 | — |
| linux/linux_kernel | ≥ 5.11, < 5.15.208 | 5.15.208 |
| linux/linux_kernel | ≥ 5.16, < 6.1.174 | 6.1.174 |
| linux/linux_kernel | ≥ 6.2, < 6.6.141 | 6.6.141 |
| linux/linux_kernel | ≥ 6.7, < 6.12.91 | 6.12.91 |
| linux/linux_kernel | ≥ 6.13, < 6.18.33 | 6.18.33 |
| linux/linux_kernel | ≥ 6.19, < 7.0.10 | 7.0.10 |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |