{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-40214", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.179Z", "datePublished": "2025-12-04T12:38:31.601Z", "dateUpdated": "2025-12-04T12:38:31.601Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-12-04T12:38:31.601Z"}, "descriptions": [{"lang": "en", "value": "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": [{"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": "d23802221f6755e104606864067c71af8cdb6788", "lessThan": "4cd8d755c7d4f515dd9abf483316aca2f1b7b0f3", "status": "affected", "versionType": "git"}, {"version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "lessThan": "db81ad20fd8aef7cc7d536c52ee5ea4c1f979128", "status": "affected", "versionType": "git"}, {"version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "lessThan": "1aa7e40ee850c9053e769957ce6541173891204d", "status": "affected", "versionType": "git"}, {"version": "ad081928a8b0f57f269df999a28087fce6f2b6ce", "lessThan": "60e6489f8e3b086bd1130ad4450a2c112e863791", "status": "affected", "versionType": "git"}, {"version": "adfb68b39b39767d6bfb53e48c4f19c183765686", "status": "affected", "versionType": "git"}]}, {"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": "6.6.117", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.59", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.9", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "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": "6.6.93", "versionEndExcluding": "6.6.117"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.12.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.17.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.18"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.141"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4cd8d755c7d4f515dd9abf483316aca2f1b7b0f3"}, {"url": "https://git.kernel.org/stable/c/db81ad20fd8aef7cc7d536c52ee5ea4c1f979128"}, {"url": "https://git.kernel.org/stable/c/1aa7e40ee850c9053e769957ce6541173891204d"}, {"url": "https://git.kernel.org/stable/c/60e6489f8e3b086bd1130ad4450a2c112e863791"}], "title": "af_unix: Initialise scc_index in unix_add_edge().", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2025-40214", "lastModified": "2025-12-04T17:15:08.283", "metrics": {}, "published": "2025-12-04T13:15:48.157", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1aa7e40ee850c9053e769957ce6541173891204d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4cd8d755c7d4f515dd9abf483316aca2f1b7b0f3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/60e6489f8e3b086bd1130ad4450a2c112e863791"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/db81ad20fd8aef7cc7d536c52ee5ea4c1f979128"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: af_unix: Initialise scc_index in unix_add_edge()", "id": "2418790", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2418790"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\naf_unix: Initialise scc_index in unix_add_edge().\nQuang Le reported that the AF_UNIX GC could garbage-collect a\nreceive queue of an alive in-flight socket, with a nice repro.\nThe repro consists of three stages.\n1)\n1-a. Create a single cyclic reference with many sockets\n1-b. close() all sockets\n1-c. Trigger GC\n2)\n2-a. Pass sk-A to an embryo sk-B\n2-b. Pass sk-X to sk-X\n2-c. Trigger GC\n3)\n3-a. accept() the embryo sk-B\n3-b. Pass sk-B to sk-C\n3-c. close() the in-flight sk-A\n3-d. Trigger GC\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:\nunix_sk(sk-A)->vertex->scc_index = 2 (UNIX_VERTEX_INDEX_START)\nunix_sk(sk-X)->vertex->scc_index = 3\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.\nAt 3-b, unix_add_edge() allocates unix_sk(sk-B)->vertex and\nlinks it to unix_unvisited_vertices.\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.\n3-c decrements sk-A's file refcnt to 1.\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:\nsk-A -> sk-B (-> sk-C)\nsk-X -> sk-X\nThis is totally fine. All of them are not yet close()d and\nshould be grouped into different SCCs.\nHowever, unix_vertex_dead() misjudges that sk-A and sk-B are\nin the same SCC and sk-A is dead.\nunix_sk(sk-A)->scc_index == unix_sk(sk-B)->scc_index <-- Wrong!\n&&\nsk-A's file refcnt == unix_sk(sk-A)->vertex->out_degree\n^-- 1 in-flight count for sk-B\n-> sk-A is dead !?\nThe problem is that unix_add_edge() does not initialise scc_index.\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.\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.\nThis way, we can continue to avoid Tarjan's algorithm while\npreventing misjudgments."], "name": "CVE-2025-40214", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-12-04T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-40214\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-40214\nhttps://lore.kernel.org/linux-cve-announce/2025120436-CVE-2025-40214-2fc6@gregkh/T"], "threat_severity": "Moderate"}