{"id":"CVE-2026-68338","title":"net/packet: avoid fanout hook re-registration after unregister","summary":"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 re…","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","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < acb40ebfa5c4d62f84339fcbf713f2a9fd033a71","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < c820f4b7f2fa38f8769db0d0cefdd94e2721504d","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 4628efbdc7affd094181f5263e65c1062e31f15f","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 80ec024d53a05c60ad1d08968dcf745f10c1665c","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 0a052e0808e015e68144a9877e6ef42b952c49fa","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 1bc55c29cd85818e9052f17deb287d5a11fb817f","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < a885387dae7986a55bae5c77a15bdd447f64e9b9","Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 50aff80475abd3533eef4320477037e6fcc6b56e","Linux 3.1"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:47:16.591778Z"},"published":"2026-08-10","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:53:08.703Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68338","references":[{"url":"https://git.kernel.org/stable/c/acb40ebfa5c4d62f84339fcbf713f2a9fd033a71"},{"url":"https://git.kernel.org/stable/c/c820f4b7f2fa38f8769db0d0cefdd94e2721504d"},{"url":"https://git.kernel.org/stable/c/4628efbdc7affd094181f5263e65c1062e31f15f"},{"url":"https://git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c"},{"url":"https://git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa"},{"url":"https://git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f"},{"url":"https://git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9"},{"url":"https://git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e"}],"tags":["cve.org"],"epss":0.00176,"epssPercentile":0.06682,"ingestedAt":"2026-10-16T17:24:46.858Z","slug":"CVE-2026-68338","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < acb40ebfa5c4d62f84339fcbf713f2a9fd033a71`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < c820f4b7f2fa38f8769db0d0cefdd94e2721504d`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 4628efbdc7affd094181f5263e65c1062e31f15f`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 80ec024d53a05c60ad1d08968dcf745f10c1665c`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 0a052e0808e015e68144a9877e6ef42b952c49fa`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 1bc55c29cd85818e9052f17deb287d5a11fb817f`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < a885387dae7986a55bae5c77a15bdd447f64e9b9`\n- `Linux >= dc99f600698dcac69b8f56dda9a8a00d645c5ffc < 50aff80475abd3533eef4320477037e6fcc6b56e`\n- `Linux 3.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}