{"id":"CVE-2026-68338","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-68338","summary":"net/packet: avoid fanout hook re-registration after unregister","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: avoid fanout hook re-registration after unregister\n\npacket_set_ring() temporarily detaches a socket from packet delivery while\nreconfiguring its ring. It records the previous running state, clears\npo->num, unregisters the protocol hook when needed, drops po->bind_lock,\nand later restores po->num and re-registers the hook from the saved\nwas_running value.\n\nThat unlocked window can race with NETDEV_UNREGISTER. The notifier can\nobserve the socket as not running, skip __unregister_prot_hook(), and\ninvalidate the per-socket binding by setting po->ifindex to -1 and clearing\npo->prot_hook.dev. A one-member fanout group can still retain its shared\nfanout hook device pointer. When packet_set_ring() resumes, re-registering\nsolely from the stale was_running state can re-add the fanout hook after\nthe device has been unregistered.\n\nTreat po->ifindex == -1 as an invalidated binding after reacquiring\npo->bind_lock. This is distinct from ifindex 0, the normal\nunbound/wildcard state: ifindex -1 marks an existing device binding that\nwas invalidated when the device was unregistered. Restore po->num as\nbefore, but do not re-register the hook if device unregister already\ndetached the socket.","published":"2026-08-10T12:03:14.549Z","modified":"2026-08-14T04:04:01.399794650Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.6.148"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68338.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68338"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:04:01.399794650Z"}}