ip: orphan prefetched skbs before multicast forwarding

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89564
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:40 UTC
Updated2026-09-11 20:19:40 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ip: orphan prefetched skbs before multicast forwarding IPv4 and IPv6 input preserve an skb->sk association installed by bpf_sk_assign() so that local delivery can use the selected socket under RCU. Both address families can also prefetch a socket in UDP early demux. In both paths (BPF and UDP early demux) a reference is not guaranteed to be held on the socket. When a multicast packet is not locally deliverable, IPv6 hands the original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the original skb when local delivery is not needed. Either path can put the skb on an unresolved multicast route queue or forward it after the receive-side RCU section ends. After the prefetched socket is destroyed, a later skb free invokes sock_pfree() and dereferences the stale skb->sk. Orphan the skb before each non-local multicast forwarding path. Local delivery retains the original skb; the existing skb_clone() calls provide multicast forwarding with a socket-free clone.

Risk And Classification

EPSS: 0.001730000 probability, percentile 0.069440000 (date 2026-09-12)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce git Not specified
CNA Linux Linux affected cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 f1281d4b99089fbaf0d3579bba62a814ebb4de4d git Not specified
CNA Linux Linux affected cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 e36ce6e78fe3fc3c071a26750783b7ba081ce10d git Not specified
CNA Linux Linux affected 5.7 Not specified
CNA Linux Linux unaffected 5.7 semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/e36ce6e78fe3fc3c071a26750783b7ba081ce10d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f1281d4b99089fbaf0d3579bba62a814ebb4de4d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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