{"id":"CVE-2026-89564","title":"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 …","summary":"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 …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 < e62aef7d6a5b27569bf540bbe11a9482117ff588","Linux >= cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 < a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce","Linux >= cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 < f1281d4b99089fbaf0d3579bba62a814ebb4de4d","Linux >= cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 < e36ce6e78fe3fc3c071a26750783b7ba081ce10d","Linux 5.7"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:23.440","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89564","references":[{"url":"https://git.kernel.org/stable/c/a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e36ce6e78fe3fc3c071a26750783b7ba081ce10d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e62aef7d6a5b27569bf540bbe11a9482117ff588","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f1281d4b99089fbaf0d3579bba62a814ebb4de4d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89564.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89564"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532326"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89564"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89564"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89564.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00138,"epssPercentile":0.03541,"scores":{"nvd":7.8,"cna":7.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.474Z","slug":"CVE-2026-89564","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89564.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208385,"id":"CVE-2026-89564","ts":1789997915220,"field":"cvss","old":"7","new":"7.8"},{"seq":205464,"id":"CVE-2026-89564","ts":1789576721071,"field":"cvss","old":"5.9","new":"7"},{"seq":205463,"id":"CVE-2026-89564","ts":1789576721071,"field":"severity","old":"medium","new":"high"},{"seq":203015,"id":"CVE-2026-89564","ts":1789403733356,"field":"cvss","old":"7.8","new":"5.9"},{"seq":203014,"id":"CVE-2026-89564","ts":1789403733356,"field":"severity","old":"high","new":"medium"},{"seq":197914,"id":"CVE-2026-89564","ts":1789384320932,"field":"cvss","old":"5.9","new":"7.8"},{"seq":197913,"id":"CVE-2026-89564","ts":1789384320932,"field":"severity","old":"medium","new":"high"},{"seq":183742,"id":"CVE-2026-89564","ts":1789356677198,"field":"cvss","old":"7.8","new":"5.9"},{"seq":183741,"id":"CVE-2026-89564","ts":1789356677198,"field":"severity","old":"high","new":"medium"},{"seq":153380,"id":"CVE-2026-89564","ts":1789285350282,"field":"cvss","old":null,"new":"7.8"},{"seq":153379,"id":"CVE-2026-89564","ts":1789285350282,"field":"severity","old":"none","new":"high"},{"seq":147371,"id":"CVE-2026-89564","ts":1789270210642,"field":"cvss","old":null,"new":"5.9"},{"seq":147370,"id":"CVE-2026-89564","ts":1789270210642,"field":"severity","old":"none","new":"medium"},{"seq":109127,"id":"CVE-2026-89564","ts":1789183730415,"field":"cvss","old":null,"new":"5.9"},{"seq":109126,"id":"CVE-2026-89564","ts":1789183730415,"field":"severity","old":"none","new":"medium"}]}