{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-22074", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.814Z", "datePublished": "2025-04-16T14:12:25.921Z", "dateUpdated": "2026-08-05T11:56:32.474Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:56:32.474Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix r_count dec/increment mismatch\n\nr_count is only increased when there is an oplock break wait,\nso r_count inc/decrement are not paired. This can cause r_count\nto become negative, which can lead to a problem where the ksmbd\nthread does not terminate." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - ksmbd is the in-kernel SMB server listening on TCP/445; the oplock/lease break path is driven entirely by SMB2 CREATE/WRITE/SET_INFO requests sent by a remote peer over the network.\nAC:L - The attacker owns both connections involved (the oplock holder and the breaker) and controls exactly how many unbalanced decrements occur by sending N writes, so `r_count` can be steered to zero or negative deterministically; no condition outside the attacker's control is needed.\nPR:L - Obtaining a level-II oplock or read-caching lease requires an open file handle, which requires a completed SMB2 session setup and tree connect with valid credentials — a low-privileged authenticated share user suffices.\nUI:N - The attacker triggers the oplock break itself by writing to or truncating the file from a second connection; no action by any local user or administrator is required.\nS:U - The corruption and its consequences (hung ksmbd kthread, freed ksmbd_conn/transport reuse) remain entirely within the kernel's own security authority.\nC:H - The underflow lets the connection teardown free `ksmbd_conn`, the transport and the socket while an in-flight work item still dereferences them, and the attacker can reoccupy that slab with request-buffer data, yielding a use-after-free read primitive over kernel memory including session keys and credentials.\nI:H - The same use-after-free gives writes through the stale `work->conn`/`work->sess` pointers and via `ksmbd_conn_write()` into freed and reallocated memory, which is the standard basis for heap-spray-driven control-flow hijacking.\nA:H - A negative `r_count` makes `wait_event(conn->r_count_q, r_count == 0)` unsatisfiable, hanging the `ksmbd:%u` kthread uninterruptibly and permanently leaking the socket, connection and sessions; this is repeatable per connection until resources are exhausted, and the UAF variant additionally causes kernel oopses." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/oplock.c" ], "versions": [ { "version": "09aeab68033161cb54f194da93e51a11aee6144b", "lessThan": "4790bcb269e5d6d88200a67c54ae6d627332a3be", "status": "affected", "versionType": "git" }, { "version": "a4261bbc33fbf99b99c80aa3a2c5097611802980", "lessThan": "457db486203c90e10c3efc87fd45cc7000b1cd36", "status": "affected", "versionType": "git" }, { "version": "f17d1c63a76b0fe8e9c78023a86507a3a6d62cfa", "lessThan": "20378cf48359f39dee0ef9b61470ebe77bd49c0d", "status": "affected", "versionType": "git" }, { "version": "3aa660c059240e0c795217182cf7df32909dd917", "lessThan": "c2ec33d46b4d1c8085dab5d02e00b21f4f0fb8a9", "status": "affected", "versionType": "git" }, { "version": "3aa660c059240e0c795217182cf7df32909dd917", "lessThan": "ddb7ea36ba7129c2ed107e2186591128618864e1", "status": "affected", "versionType": "git" }, { "version": "6.6.84", "lessThan": "6.6.87", "status": "affected", "versionType": "semver" }, { "version": "6.12.20", "lessThan": "6.12.23", "status": "affected", "versionType": "semver" }, { "version": "6.13.8", "lessThan": "6.13.11", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/oplock.c" ], "versions": [ { "version": "6.14", "status": "affected" }, { "version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.87", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.23", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.11", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14.2", "lessThanOrEqual": "6.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15", "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": "6.6.84", "versionEndExcluding": "6.6.87" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.20", "versionEndExcluding": "6.12.23" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13.8", "versionEndExcluding": "6.13.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.14.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4790bcb269e5d6d88200a67c54ae6d627332a3be" }, { "url": "https://git.kernel.org/stable/c/457db486203c90e10c3efc87fd45cc7000b1cd36" }, { "url": "https://git.kernel.org/stable/c/20378cf48359f39dee0ef9b61470ebe77bd49c0d" }, { "url": "https://git.kernel.org/stable/c/c2ec33d46b4d1c8085dab5d02e00b21f4f0fb8a9" }, { "url": "https://git.kernel.org/stable/c/ddb7ea36ba7129c2ed107e2186591128618864e1" } ], "title": "ksmbd: fix r_count dec/increment mismatch", "x_generator": { "engine": "bippy-1.2.0" } } } }