{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-40214", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-40214", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-12-04T12:38:31.601Z", "updatedAt": "2026-08-05T12:08:39.553Z", "importedAt": "2026-10-24T01:57:34.152Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "af_unix: Initialise scc_index in unix_add_edge().", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Initialise scc_index in unix_add_edge().\n\nQuang Le reported that the AF_UNIX GC could garbage-collect a\nreceive queue of an alive in-flight socket, with a nice repro.\n\nThe repro consists of three stages.\n\n 1)\n 1-a. Create a single cyclic reference with many sockets\n 1-b. close() all sockets\n 1-c. Trigger GC\n\n 2)\n 2-a. Pass sk-A to an embryo sk-B\n 2-b. Pass sk-X to sk-X\n 2-c. Trigger GC\n\n 3)\n 3-a. accept() the embryo sk-B\n 3-b. Pass sk-B to sk-C\n 3-c. close() the in-flight sk-A\n 3-d. Trigger GC\n\nAs of 2-c, sk-A and sk-X are linked to unix_unvisited_vertices,\nand unix_walk_scc() groups them into two different SCCs:\n\n unix_sk(sk-A)->vertex->scc_index = 2 (UNIX_VERTEX_INDEX_START)\n unix_sk(sk-X)->vertex->scc_index = 3\n\nOnce GC completes, unix_graph_grouped is set to true.\nAlso, unix_graph_maybe_cyclic is set to true due to sk-X's\ncyclic self-reference, which makes close() trigger GC.\n\nAt 3-b, unix_add_edge() allocates unix_sk(sk-B)->vertex and\nlinks it to unix_unvisited_vertices.\n\nunix_update_graph() is called at 3-a. and 3-b., but neither\nunix_graph_grouped nor unix_graph_maybe_cyclic is changed\nbecause both sk-B's listener and sk-C are not in-flight.\n\n3-c decrements sk-A's file refcnt to 1.\n\nSince unix_graph_grouped is true at 3-d, unix_walk_scc_fast()\nis finally called and iterates 3 sockets sk-A, sk-B, and sk-X:\n\n sk-A -> sk-B (-> sk-C)\n sk-X -> sk-X\n\nThis is totally fine. All of them are not yet close()d and\nshould be grouped into different SCCs.\n\nHowever, unix_vertex_dead() misjudges that sk-A and sk-B are\nin the same SCC and sk-A is dead.\n\n unix_sk(sk-A)->scc_index == unix_sk(sk-B)->scc_index <-- Wrong!\n &&\n sk-A's file refcnt == unix_sk(sk-A)->vertex->out_degree\n ^-- 1 in-flight count for sk-B\n -> sk-A is dead !?\n\nThe problem is that unix_add_edge() does not initialise scc_index.\n\nStage 1) is used for heap spraying, making a newly allocated\nvertex have vertex->scc_index == 2 (UNIX_VERTEX_INDEX_START)\nset by unix_walk_scc() at 1-c.\n\nLet's track the max SCC index from the previous unix_walk_scc()\ncall and assign the max + 1 to a new vertex's scc_index.\n\nThis way, we can continue to avoid Tarjan's algorithm while\npreventing misjudgments.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "adfb68b39b39767d6bfb53e48c4f19c183765686", "status": "affected", "versionType": "git", "lessThan": "20003fbb9174121b27bd1da6ebe61542ac4c327d" }, { "version": "d23802221f6755e104606864067c71af8cdb6788", "status": "affected", "versionType": "git", "lessThan": "4cd8d755c7d4f515dd9abf483316aca2f1b7b0f3" }, { "version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "status": "affected", "versionType": "git", "lessThan": "db81ad20fd8aef7cc7d536c52ee5ea4c1f979128" }, { "version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "status": "affected", "versionType": "git", "lessThan": "1aa7e40ee850c9053e769957ce6541173891204d" }, { "version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "status": "affected", "versionType": "git", "lessThan": "60e6489f8e3b086bd1130ad4450a2c112e863791" }, { "version": "6.1.141", "status": "affected", "versionType": "semver", "lessThan": "6.1.159" }, { "version": "6.6.93", "status": "affected", "versionType": "semver", "lessThan": "6.6.117" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.10" }, { "version": "6.1.159", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.117", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.59", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.17.9", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.17.*" }, { "version": "6.18", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }