{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80521","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.763Z","datePublished":"2026-08-26T14:37:02.589Z","dateUpdated":"2026-09-21T13:14:08.756Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-21T13:14:08.756Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Unlink scc_entry in unix_del_edge().\n\nKyle Zeng reported that GC could free a dead SCC partially.\n\nThe scenario is as follows:\n\n   1) Create two SCCs:\n\n       X -.   A <-> B\n       ^--'\n\n   2) Run the following concurrently:\n\n      2-1) send() sk-B to sk-B from sk-X\n      2-2) close() both A and B\n\nAt 2-1), there is a small window where unix_add_edges()\npublishes a new edge (B <-> B) to GC but its skb is not queued\nby skb_queue_tail().\n\nIf 2-2) completes before skb_queue_tail() and GC is triggered,\nit judges A <-> B as dead, but B is not freed because GC cannot\ncollect the not-yet-queued skb holding the B <-> B edge.\n\n       X -.   A <-> B -. This edge is visible\n       ^--'         ^..'  but skb is not\n\nThis itself is not a problem since the next GC run will judge\nB as dead as well and free it finally.\n\n       X -.   A <.> B -.\n       ^--'         ^--'\n\nHowever, X's SCC forces the next GC to call unix_walk_scc_fast(),\nand it iterates over A through B's scc_entry.\n\nLet's unlink scc_entry before freeing the vertex in unix_del_edge()."}],"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 only reachable through local AF_UNIX syscalls (socket/sendmsg with SCM_RIGHTS and close) that drive unix_add_edges(), unix_del_edge(), and unix_gc(); AF_UNIX is host-local IPC with no remote packet, Bluetooth, WiFi, or physical bus entry path.\nAC:L - Exploitation requires racing sendmsg() (scm_stat_add/unix_add_edges before skb_queue_tail) against concurrent close() that triggers GC; the attacker controls both threads, can pin CPUs, and can retry until the window is hit, so success does not depend on conditions outside attacker control.\nPR:L - An unprivileged local user can create AF_UNIX sockets, pass socket file descriptors via SCM_RIGHTS to form inflight reference cycles, and close sockets to schedule unix_gc(); no real-root capabilities, special namespaces, or non-default kernel configuration are required.\nUI:N - The attacker sets up the cyclic inflight graph, performs the concurrent self-send and close operations, and forces garbage collection from its own processes; no separate victim user action or cooperating peer is needed beyond the attacker's own sockets.\nS:U - The use-after-free corrupts kernel heap/list state during AF_UNIX garbage collection within the same kernel security authority; exploitation yields standard local privilege escalation rather than crossing a VM, IOMMU, or inter-tenant sandbox boundary.\nC:H - Freed struct unix_vertex objects remain linked through stale scc_entry; unix_walk_scc_fast(), unix_scc_dead(), and unix_collect_skb() dereference freed vertex->edges and predecessor socket receive queues, giving a slab UAF read primitive controllable through heap grooming.\nI:H - The same UAF enables reclaiming freed vertices and influencing GC list iteration and skb_queue_splice_init() during unix_collect_skb(), providing memory corruption primitives suitable for arbitrary kernel writes, control-flow hijack, and local privilege escalation.\nA:H - Iterating or collecting through a freed vertex reliably triggers kernel oops/panic (KASAN slab-use-after-free), and corrupt GC graph state can crash the host or deny service to local workloads even when full exploitation is not attempted."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/garbage.c"],"versions":[{"version":"4090fa373f0e763c43610853d2774b5979915959","lessThan":"1293fd69a50d188a5788b08ba3741a3e86be1608","status":"affected","versionType":"git"},{"version":"4090fa373f0e763c43610853d2774b5979915959","lessThan":"fe198b077864feafd4aa4b33b1a5ce26f50195a2","status":"affected","versionType":"git"},{"version":"4090fa373f0e763c43610853d2774b5979915959","lessThan":"e3702470ced94fad74d71e2232f022d2eb752a6d","status":"affected","versionType":"git"},{"version":"4090fa373f0e763c43610853d2774b5979915959","lessThan":"594d905195024b228c962627ae5ae7c17bd582a4","status":"affected","versionType":"git"},{"version":"5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a","status":"affected","versionType":"git"},{"version":"de7921631ff323369aa63a4324695ab54ea4047e","status":"affected","versionType":"git"},{"version":"6.1.141","lessThan":"6.2","status":"affected","versionType":"semver"},{"version":"6.6.93","lessThan":"6.7","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/garbage.c"],"versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.10","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":"6.10","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.1.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.141"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.93"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1293fd69a50d188a5788b08ba3741a3e86be1608"},{"url":"https://git.kernel.org/stable/c/fe198b077864feafd4aa4b33b1a5ce26f50195a2"},{"url":"https://git.kernel.org/stable/c/e3702470ced94fad74d71e2232f022d2eb752a6d"},{"url":"https://git.kernel.org/stable/c/594d905195024b228c962627ae5ae7c17bd582a4"}],"title":"af_unix: Unlink scc_entry in unix_del_edge().","x_generator":{"engine":"bippy-1.2.0"}}}}