{"cve":"CVE-2026-89564","nvd":{"published":"2026-09-11T20:19:40.313","modified":"2026-10-21T13:20:08.687","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nip: orphan prefetched skbs before multicast forwarding\n\nIPv4 and IPv6 input preserve an skb->sk association installed by\nbpf_sk_assign() so that local delivery can use the selected socket under\nRCU. Both address families can also prefetch a socket in UDP early demux.\nIn both paths (BPF and UDP early demux) a reference is not guaranteed to\nbe held on the socket.\n\nWhen a multicast packet is not locally deliverable, IPv6 hands the\noriginal skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the\noriginal skb when local delivery is not needed. Either path can put the\nskb on an unresolved multicast route queue or forward it after the\nreceive-side RCU section ends.\n\nAfter the prefetched socket is destroyed, a later skb free invokes\nsock_pfree() and dereferences the stale skb->sk. Orphan the skb before\neach non-local multicast forwarding path. Local delivery retains the\noriginal skb; the existing skb_clone() calls provide multicast forwarding\nwith a socket-free clone.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/882212d317a7c16ab70d20656f6b1c42abada9f6","https://git.kernel.org/stable/c/a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce","https://git.kernel.org/stable/c/e36ce6e78fe3fc3c071a26750783b7ba081ce10d","https://git.kernel.org/stable/c/e62aef7d6a5b27569bf540bbe11a9482117ff588","https://git.kernel.org/stable/c/f1281d4b99089fbaf0d3579bba62a814ebb4de4d"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-89564","score":0.00138,"percentile":0.03199,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}