CVE-2026-46300 · CVSS 7.8 HIGH · EPSS 10% · KEV 2026-10-28 · patch available
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.
Is CVE-2026-46300 exploited?
Listed in the CISA KEV catalog on 2026-10-28.
Federal remediation due 2026-10-31.
EPSS puts exploitation in the next 30 days at 10%.
Public exploit code: packaged in a public tool.
Which products and versions are affected?
Linux · Linux · >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 3599e6b3cc1ada96883d496a50a210d3afbb6987, >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c, >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5, >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 78bf6b6bb19541d19fbda6242e7cfe2c682763c0, >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e, >= cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 3bd9e113d50034db99d7ef69fd8e5242d15e414a, +2 more (except the fixed hotfixes listed under "Is there a patch?")