{"api_version":"1","generated_at":"2026-08-20T17:59:24+00:00","cve":"CVE-2026-68338","urls":{"html":"https://cve.report/CVE-2026-68338","api":"https://cve.report/api/cve/CVE-2026-68338.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-68338","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-68338"},"summary":{"title":"net/packet: avoid fanout hook re-registration after unregister","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-10 13:20:24","updated_at":"2026-08-19 17:20:43"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","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","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","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","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa","name":"https://git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e","name":"https://git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f","name":"https://git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/acb40ebfa5c4d62f84339fcbf713f2a9fd033a71","name":"https://git.kernel.org/stable/c/acb40ebfa5c4d62f84339fcbf713f2a9fd033a71","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4628efbdc7affd094181f5263e65c1062e31f15f","name":"https://git.kernel.org/stable/c/4628efbdc7affd094181f5263e65c1062e31f15f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c820f4b7f2fa38f8769db0d0cefdd94e2721504d","name":"https://git.kernel.org/stable/c/c820f4b7f2fa38f8769db0d0cefdd94e2721504d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c","name":"https://git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9","name":"https://git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68338","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68338","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc acb40ebfa5c4d62f84339fcbf713f2a9fd033a71 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc c820f4b7f2fa38f8769db0d0cefdd94e2721504d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc 4628efbdc7affd094181f5263e65c1062e31f15f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc 80ec024d53a05c60ad1d08968dcf745f10c1665c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc 0a052e0808e015e68144a9877e6ef42b952c49fa git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc 1bc55c29cd85818e9052f17deb287d5a11fb817f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc a885387dae7986a55bae5c77a15bdd447f64e9b9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc99f600698dcac69b8f56dda9a8a00d645c5ffc 50aff80475abd3533eef4320477037e6fcc6b56e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.265 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.216 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.183 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.148 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.101 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"68338","cve":"CVE-2026-68338","epss":"0.001750000","percentile":"0.073370000","score_date":"2026-08-19","updated_at":"2026-08-20 00:13:09"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/packet/af_packet.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"acb40ebfa5c4d62f84339fcbf713f2a9fd033a71","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"c820f4b7f2fa38f8769db0d0cefdd94e2721504d","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"4628efbdc7affd094181f5263e65c1062e31f15f","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"80ec024d53a05c60ad1d08968dcf745f10c1665c","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"0a052e0808e015e68144a9877e6ef42b952c49fa","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"1bc55c29cd85818e9052f17deb287d5a11fb817f","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"a885387dae7986a55bae5c77a15bdd447f64e9b9","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"},{"lessThan":"50aff80475abd3533eef4320477037e6fcc6b56e","status":"affected","version":"dc99f600698dcac69b8f56dda9a8a00d645c5ffc","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/packet/af_packet.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.1"},{"lessThan":"3.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.265","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.216","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.183","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.148","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.101","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.265","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.216","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.183","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.148","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.101","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"3.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"3.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The bug is triggered through local syscalls — creating an AF_PACKET socket, PACKET_FANOUT/bind setsockopt, PACKET_RX_RING setsockopt, and a netlink device unregister — with no remote packet processing involved.\nAC:L - The attacker controls both sides of the race: it issues the packet_set_ring() reconfiguration and deletes the bound netdev in its own netns, and the unlocked window spans synchronize_net() plus the ring swap, making it wide and reliably winnable.\nPR:L - AF_PACKET requires CAP_NET_RAW and device unregistration CAP_NET_ADMIN, but an unprivileged user obtains both via user+network namespaces (unshare -Urn) and can create and delete veth/dummy devices there.\nUI:N - The attacker performs every step itself — socket setup, ring reconfiguration and device teardown — with no action required from any other user.\nS:U - The stale hook registration and resulting corruption stay within the kernel's own security authority; no hypervisor, IOMMU or other trust boundary is crossed.\nC:H - The fanout packet_type is left linked into a net_device that is being torn down, a dangling registration on soon-to-be-freed memory; such stale-pointer state in the ptype lists can be leveraged for kernel memory disclosure.\nI:H - The dangling list node in the freed net_device's ptype list yields a list_del write into freed memory when the hook is later removed, a controllable write primitive typical of use-after-free exploitation.\nA:H - The re-added hook makes netdev_run_todo() hit BUG_ON(!list_empty(&dev->ptype_all)) while RTNL is held, oopsing the kernel and permanently wedging all further network configuration — a repeatable, unprivileged host-wide denial of service."}]}],"providerMetadata":{"dateUpdated":"2026-08-19T16:33:38.308Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}],"title":"net/packet: avoid fanout hook re-registration after unregister","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-68338","datePublished":"2026-08-10T12:03:14.549Z","dateReserved":"2026-07-30T09:28:09.384Z","dateUpdated":"2026-08-19T16:33:38.308Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-10 13:20:24","lastModifiedDate":"2026-08-19 17:20:43","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"68338","Ordinal":"1","Title":"net/packet: avoid fanout hook re-registration after unregister","CVE":"CVE-2026-68338","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"68338","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"net/packet: avoid fanout hook re-registration after unregister"}]}}}