CVE-2025-21988

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-21988", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.800Z", "datePublished": "2025-04-02T12:53:12.170Z", "dateUpdated": "2026-08-05T11:55:52.895Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:52.895Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/netfs/read_collect: add to next->prev_donated\n\nIf multiple subrequests donate data to the same \"next\" request\n(depending on the subrequest completion order), each of them would\noverwrite the `prev_donated` field, causing data corruption and a\nBUG() crash (\"Can't donate prior to front\")."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The vulnerable donation accounting in fs/netfs is driven entirely by data returned from a remote peer \u2014 subrequest completion order, short-read lengths and non-folio-aligned boundaries are chosen by the SMB/9p/Ceph/AFS server, and `netfs_read_subreq_terminated()` is invoked directly from those filesystems' network receive paths. A malicious or compromised file server, or an on-path attacker against an unsigned/unencrypted cifs, 9p or NFS mount, reaches the bug over the network.\nAC:L - The remote server controls both sides of the race: it decides when each READ response is sent and how much data it carries, so it can deterministically make two subrequests donate to the same successor and clobber `prev_donated`. The bug was reported from ordinary production use rather than a targeted fuzz, and the affected filesystems are enabled in all mainstream kernel configs.\nPR:N - The attacker is the remote server (or an on-path attacker) and needs no credentials or account on the victim host \u2014 only that the victim have a netfs-backed mount it reads from. No local privilege on the target is involved.\nUI:N - Ordinary background readahead on an already-mounted share (fstab/automount, container volume, WSL/Kata 9p, backup or indexer scans) is enough to drive the read-collection path; no specific victim action is required.\nS:U - The corruption and crash are confined to the kernel's own page cache and netfs request state; no VM, IOMMU or sandbox boundary is crossed.\nC:H - Lost donations make `netfs_unlock_read_folio()` mark folios uptodate for ranges no subrequest ever filled and inflate `rreq->transferred`, so read() returns uninitialized page-cache pages \u2014 arbitrary previously-freed kernel memory \u2014 to userspace, and the collector can also walk off the folio queue into invalid `folioq` pointers.\nI:H - The commit states the bug causes data corruption; because `NETFS_READ_FOR_WRITE` is one of the affected origins, a folio wrongly marked uptodate with unfilled content is subsequently written back, persisting corrupted data to the file on the server, and the broken start/len/transferred bookkeeping corrupts page-cache state generally.\nA:H - The mis-accounting hits an explicit `BUG()` (\"Can't donate prior to front\"/\"fpos > start\") in the filesystem completion context, killing the worker or softirq while rolling-buffer folios remain locked \u2014 a kernel panic, or at minimum an unrecoverable hang of every task waiting on those folios and of the mount."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/netfs/read_collect.c"], "versions": [{"version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "lessThan": "62b9ad7e52d4777f7e775ee1f0ad2452f6041024", "status": "affected", "versionType": "git"}, {"version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "lessThan": "e25cec3b76aba47a49138d2162fc809c6cd49c9e", "status": "affected", "versionType": "git"}, {"version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "lessThan": "e2d46f2ec332533816417b60933954173f602121", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/netfs/read_collect.c"], "versions": [{"version": "6.12", "status": "affected"}, {"version": "0", "lessThan": "6.12", "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": "6.12", "versionEndExcluding": "6.12.20"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.13.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.14"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/62b9ad7e52d4777f7e775ee1f0ad2452f6041024"}, {"url": "https://git.kernel.org/stable/c/e25cec3b76aba47a49138d2162fc809c6cd49c9e"}, {"url": "https://git.kernel.org/stable/c/e2d46f2ec332533816417b60933954173f602121"}], "title": "fs/netfs/read_collect: add to next->prev_donated", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/netfs/read_collect.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "62b9ad7e52d4777f7e775ee1f0ad2452f6041024", "status": "affected", "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "versionType": "git"}, {"lessThan": "e25cec3b76aba47a49138d2162fc809c6cd49c9e", "status": "affected", "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "versionType": "git"}, {"lessThan": "e2d46f2ec332533816417b60933954173f602121", "status": "affected", "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/netfs/read_collect.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.12"}, {"lessThan": "6.12", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.20", "versionType": "semver"}, {"lessThanOrEqual": "6.13.*", "status": "unaffected", "version": "6.13.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "F6AE02FC-5B2D-426A-B8D7-3D71FBE28D40", "versionEndExcluding": "6.12.20", "versionStartIncluding": "6.12", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "0A20D4D7-B329-4C68-B662-76062EA7DCF0", "versionEndExcluding": "6.13.8", "versionStartIncluding": "6.13", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/netfs/read_collect: add to next->prev_donated\n\nIf multiple subrequests donate data to the same \"next\" request\n(depending on the subrequest completion order), each of them would\noverwrite the `prev_donated` field, causing data corruption and a\nBUG() crash (\"Can't donate prior to front\")."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fs/netfs/read_collect: agregar a next->prev_doned Si varias subsolicitudes donan datos a la misma solicitud \"siguiente\" (dependiendo del orden de finalizaci\u00f3n de las subsolicitudes), cada una de ellas sobrescribir\u00eda el campo `prev_doned`, lo que causar\u00eda corrupci\u00f3n de datos y un bloqueo de BUG() (\"No se puede donar antes del front\")."}], "id": "CVE-2025-21988", "lastModified": "2026-07-30T06:22:01.917", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2025-04-02T13:15:43.317", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/62b9ad7e52d4777f7e775ee1f0ad2452f6041024"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e25cec3b76aba47a49138d2162fc809c6cd49c9e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e2d46f2ec332533816417b60933954173f602121"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: fs/netfs/read_collect: add to next->prev_donated", "id": "2356906", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2356906"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-99", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nfs/netfs/read_collect: add to next->prev_donated\nIf multiple subrequests donate data to the same \"next\" request\n(depending on the subrequest completion order), each of them would\noverwrite the `prev_donated` field, causing data corruption and a\nBUG() crash (\"Can't donate prior to front\")."], "name": "CVE-2025-21988", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "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": "2025-04-02T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-21988\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-21988\nhttps://lore.kernel.org/linux-cve-announce/2025040254-CVE-2025-21988-e048@gregkh/T"], "threat_severity": "Moderate"}

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