{"id":"CVE-2026-98289","title":"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 …","summary":"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 …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4090fa373f0e763c43610853d2774b5979915959 < b8f71d69380a5fbc734c868acbeb560f1de1766f","Linux >= 4090fa373f0e763c43610853d2774b5979915959 < be550ee108ad80828aa61280400bedfc7e7c39d3","Linux >= 4090fa373f0e763c43610853d2774b5979915959 < 4a4263dfeabad72f95e8ab6e15146861fa4144dd","Linux 5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a","Linux de7921631ff323369aa63a4324695ab54ea4047e","Linux >= 6.1.141 < 6.2","Linux >= 6.6.93 < 6.7","Linux 6.10"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:19.177","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98289","references":[{"url":"https://git.kernel.org/stable/c/4a4263dfeabad72f95e8ab6e15146861fa4144dd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b8f71d69380a5fbc734c868acbeb560f1de1766f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/be550ee108ad80828aa61280400bedfc7e7c39d3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.420Z","slug":"CVE-2026-98289","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}