{"cve":"CVE-2026-98289","nvd":{"published":"2026-10-06T09:18:19.177","modified":"2026-10-19T10:18:30.560","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Unify scc_index when finalising SCC in __unix_walk_scc().\n\nCommit bfdb01283ee8 (\"af_unix: Assign a unique index to SCC.\")\nchanged Tarjan's algorithm to update lowlink with lowlink,\nwhich is called lowpoint (unix_vertex.scc_index).\n\nunix_vertex_dead() assumes all vertices in an SCC share the same\nlowpoint, but this is not always true if an SCC has two or more\nback edges, depending on the order of DFS.\n\nFor example, the graph below has two back edges from B to A\nand from C to B.\n\n  A --> B --> C\n  ^    | ^    |\n  `----' `----'\n\nIf DFS walks through A -> B -> C -> B (-> C -> B) -> A (-> B -> A),\neach index and scc_index will be updated as follows.\n\n  A --> B --> C    C = (3, 3)  (index, scc_index)\n                   B = (2, 2)\n                   A = (1, 1)\n\n  A ... B ... C    C = (3, 2)<-.\n         ^    |    B = (2, 2) -'\n         `----'    A = (1, 1)\n\n  A ... B ... C    C = (3, 2)\n  ^    | .    .    B = (2, 1)<-.\n  `----'  ....     A = (1, 1) -'\n\nThen, unix_vertex_dead() thinks that B is passed to another\nSCC with scc_index 2, and the SCC is not garbage-collected.\n\nThis does not happen if DFS walks in a different order below\nor starts from B.\n\n    1      3\n  A --> B --> C\n  ^    | ^    |\n  `----' `----'\n     2      4\n\nLet's unify scc_index across the SCC when finalising it.\n\nNote that updating v->index was previously done in unix_scc_dead(),\nwhen called from __unix_walk_scc(), just to save one loop.  Since\n__unix_walk_scc() now iterates over the SCC anyway, the update is\nmoved back to __unix_walk_scc() and 'fast' argument is dropped.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/4a4263dfeabad72f95e8ab6e15146861fa4144dd","https://git.kernel.org/stable/c/b8f71d69380a5fbc734c868acbeb560f1de1766f","https://git.kernel.org/stable/c/be550ee108ad80828aa61280400bedfc7e7c39d3"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:57:46.668721662+00:00"},"epss":{"cve":"CVE-2026-98289","score":0.00166,"percentile":0.05774,"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."]}