{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68338", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.384Z", "datePublished": "2026-08-10T12:03:14.549Z", "dateUpdated": "2026-08-19T16:33:38.308Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:33:38.308Z" }, "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": { "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" }, "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/packet/af_packet.c" ], "versions": [ { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "acb40ebfa5c4d62f84339fcbf713f2a9fd033a71", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "c820f4b7f2fa38f8769db0d0cefdd94e2721504d", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "4628efbdc7affd094181f5263e65c1062e31f15f", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "80ec024d53a05c60ad1d08968dcf745f10c1665c", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "0a052e0808e015e68144a9877e6ef42b952c49fa", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "1bc55c29cd85818e9052f17deb287d5a11fb817f", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "a885387dae7986a55bae5c77a15bdd447f64e9b9", "status": "affected", "versionType": "git" }, { "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc", "lessThan": "50aff80475abd3533eef4320477037e6fcc6b56e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/packet/af_packet.c" ], "versions": [ { "version": "3.1", "status": "affected" }, { "version": "0", "lessThan": "3.1", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }