Linux kernel: skb sharedfrag flag mispropagated in fragtransfer helpers
CVE-2026-46300 Published on May 23, 2026
net: skbuff: preserve shared-frag marker during coalescing
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.
Products Associated with CVE-2026-46300
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Affected Versions
Linux:- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 3599e6b3cc1ada96883d496a50a210d3afbb6987 is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5 is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 78bf6b6bb19541d19fbda6242e7cfe2c682763c0 is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 3bd9e113d50034db99d7ef69fd8e5242d15e414a is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below 3884358a9286b17f389a72b1426fc4547c23c111 is affected.
- Version cef401de7be8c4e155c6746bfccf721a4fa5fab9 and below f84eca5817390257cef78013d0112481c503b4a3 is affected.
- Version 3.9 is affected.
- Before 3.9 is unaffected.
- Version 5.10.257, <= 5.10.* is unaffected.
- Version 5.15.208, <= 5.15.* is unaffected.
- Version 6.1.174, <= 6.1.* is unaffected.
- Version 6.6.141, <= 6.6.* is unaffected.
- Version 6.12.91, <= 6.12.* is unaffected.
- Version 6.18.33, <= 6.18.* is unaffected.
- Version 7.0.10, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.