{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21966", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.796Z", "datePublished": "2025-04-01T15:47:01.836Z", "dateUpdated": "2026-08-05T11:55:42.212Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:42.212Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-flakey: Fix memory corruption in optional corrupt_bio_byte feature\n\nFix memory corruption due to incorrect parameter being passed to bio_init" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The corruption is triggered by write I/O submitted locally to a dm-flakey block device or a filesystem mounted on it; there is no remote or network-facing path into drivers/md/dm-flakey.c.\nAC:L - Once the target is configured, every matching write bio during the down interval deterministically overflows the neighbouring slab object — no race to win and the up/down cycle is periodic and predictable, so the attacker simply writes or retries.\nPR:L - Creating the dm-flakey table needs CAP_SYS_ADMIN, but on the systems where this feature is actually deployed (fstests/CI/QA fault-injection hosts) any unprivileged user with write access to the device or its mounted filesystem triggers the out-of-bounds write with ordinary writes.\nUI:N - The attacker's own writes drive the corruption; no action by another user or administrator is needed beyond the pre-existing device configuration.\nS:U - The out-of-bounds write corrupts kernel slab memory within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The clone's bvec array aliases memory outside the original bio's allocation, and the subsequent `bio_for_each_folio_all()`/`folio_put()` walk reads back whatever now occupies that neighbouring live object, giving a controlled heap corruption primitive usable for arbitrary kernel memory disclosure.\nI:H - This is a direct heap out-of-bounds write of `struct bio_vec` records (page pointer, length, offset) into adjacent slab objects — from 16 bytes up to ~16 KB under attacker-inducible allocation-order fallback — a classic exploitable primitive for pointer corruption and control-flow hijack.\nA:H - Corrupting adjacent `dm_io`/`dm_target_io`/bio structures and calling `folio_put()` on garbage pointers reliably produces oopses, BUG_ONs, and page refcount corruption leading to kernel panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/dm-flakey.c" ], "versions": [ { "version": "1d9a943898533e83f20370c0e1448d606627522e", "lessThan": "818330f756f3800c37d738bd36bce60eac949938", "status": "affected", "versionType": "git" }, { "version": "1d9a943898533e83f20370c0e1448d606627522e", "lessThan": "5a87e46da2418c57b445371f5ca0958d5779ba5f", "status": "affected", "versionType": "git" }, { "version": "1d9a943898533e83f20370c0e1448d606627522e", "lessThan": "da070843e153471be4297a12fdaa64023276f40e", "status": "affected", "versionType": "git" }, { "version": "1d9a943898533e83f20370c0e1448d606627522e", "lessThan": "57e9417f69839cb10f7ffca684c38acd28ceb57b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/dm-flakey.c" ], "versions": [ { "version": "6.5", "status": "affected" }, { "version": "0", "lessThan": "6.5", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.84", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.20", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.8", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "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": "6.5", "versionEndExcluding": "6.6.84" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.12.20" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.13.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/818330f756f3800c37d738bd36bce60eac949938" }, { "url": "https://git.kernel.org/stable/c/5a87e46da2418c57b445371f5ca0958d5779ba5f" }, { "url": "https://git.kernel.org/stable/c/da070843e153471be4297a12fdaa64023276f40e" }, { "url": "https://git.kernel.org/stable/c/57e9417f69839cb10f7ffca684c38acd28ceb57b" } ], "title": "dm-flakey: Fix memory corruption in optional corrupt_bio_byte feature", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "cweId": "CWE-787", "lang": "en", "description": "CWE-787 Out-of-bounds Write" } ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2025-10-01T18:16:20.613850Z", "id": "CVE-2025-21966", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-01T18:16:24.672Z" } } ] } }