{"cve":"CVE-2026-80521","nvd":{"published":"2026-08-26T15:17:05.677","modified":"2026-10-03T11:17:39.437","status":"Received","description":"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().","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/1293fd69a50d188a5788b08ba3741a3e86be1608","https://git.kernel.org/stable/c/2b6c2842692d08e7acaf32d1eb47f95def35f3fe","https://git.kernel.org/stable/c/594d905195024b228c962627ae5ae7c17bd582a4","https://git.kernel.org/stable/c/6fda5c51b8e43a8440f76e65c89d9f95ddb2ef33","https://git.kernel.org/stable/c/e3702470ced94fad74d71e2232f022d2eb752a6d"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-80521","score":0.00178,"percentile":0.07263,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}