{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89685", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.749Z", "datePublished": "2026-09-11T19:46:07.116Z", "dateUpdated": "2026-10-21T12:48:20.051Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:48:20.051Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix clock domain mismatch in clients_still_reclaiming()\n\nclients_still_reclaiming() computes a deadline from nn->boot_time\n(CLOCK_REALTIME, ~1.7 billion) but compares it against\nktime_get_boottime_seconds() (CLOCK_BOOTTIME, seconds since boot).\nThe comparison is always false — it would take ~54 years of uptime\nfor BOOTTIME to exceed the REALTIME-derived deadline.\n\nThis means any client can hold the server in grace indefinitely by\nsending CLAIM_PREVIOUS OPEN requests, blocking all non-reclaim\noperations for all other clients.\n\nAdd boot_time_bt (CLOCK_BOOTTIME) alongside the existing boot_time\nand use it for the deadline computation. boot_time (CLOCK_REALTIME)\nis preserved for its cl_boot clientid-nonce role." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - nfsd processes NFSv4 COMPOUND OPEN over TCP (typically port 2049). A remote peer reaches clients_still_reclaiming() by sending CLAIM_PREVIOUS OPEN or reclaim LOCK, which sets NFSD_NET_SOMEBODY_RECLAIMED and prevents grace from ending.\nAC:L - The attacker fully controls the reclaim OPEN/LOCK RPCs that keep NFSD_NET_SOMEBODY_RECLAIMED set; no race or memory layout is required. Grace always starts with nfsd, and the broken REALTIME-vs-BOOTTIME deadline never fires, so the attacker can extend it at will.\nPR:N - Default nfsd exports accept AUTH_SYS/AUTH_NULL with no credentials. An unauthenticated network peer that is or becomes a recorded NFSv4 client can send CLAIM_PREVIOUS OPEN; no server account or capability is required.\nUI:N - Exploitation takes only attacker-sent NFSv4 RPCs after nfsd starts; no victim user action such as mounting or opening a file is required.\nS:U - The impact stays in the same kernel nfsd/lockd grace state. This is a service denial on the NFS server, not a VM, IOMMU, or sandbox boundary crossing.\nC:N - The bug only miscompares grace deadlines and extends the grace period. It does not disclose kernel memory or file contents.\nI:N - No unauthorized modification of kernel or file data occurs. Other clients are blocked from new mutating operations, which is an availability effect rather than an integrity violation.\nA:H - Successful reclaim OPENs hold nfsd in grace indefinitely because the double-lease deadline never expires, so non-reclaim OPEN/REMOVE/RENAME/SETXATTR and lockd grace return NFS4ERR_GRACE and fully deny NFSv4 service to other clients." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/netns.h", "fs/nfsd/nfs4state.c" ], "versions": [ { "version": "20b7d86f29d39e8ae19bb29c24ffee70dc385ddf", "lessThan": "04c3e4456fe76e8d7c94171009df3165c3262c51", "status": "affected", "versionType": "git" }, { "version": "20b7d86f29d39e8ae19bb29c24ffee70dc385ddf", "lessThan": "e92e80c5b043108029bc729b30d12c37158fb9cb", "status": "affected", "versionType": "git" }, { "version": "20b7d86f29d39e8ae19bb29c24ffee70dc385ddf", "lessThan": "f9cec313efb2fd18d962aad738a4892bce806016", "status": "affected", "versionType": "git" }, { "version": "20b7d86f29d39e8ae19bb29c24ffee70dc385ddf", "lessThan": "9843649196221152b6e5d138a3ce859bdaae1d96", "status": "affected", "versionType": "git" }, { "version": "20b7d86f29d39e8ae19bb29c24ffee70dc385ddf", "lessThan": "09ea3eb9a518565f5bca386e81b993ed8825f5e8", "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/nfsd/netns.h", "fs/nfsd/nfs4state.c" ], "versions": [ { "version": "5.6", "status": "affected" }, { "version": "0", "lessThan": "5.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.6", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.6", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/04c3e4456fe76e8d7c94171009df3165c3262c51" }, { "url": "https://git.kernel.org/stable/c/e92e80c5b043108029bc729b30d12c37158fb9cb" }, { "url": "https://git.kernel.org/stable/c/f9cec313efb2fd18d962aad738a4892bce806016" }, { "url": "https://git.kernel.org/stable/c/9843649196221152b6e5d138a3ce859bdaae1d96" }, { "url": "https://git.kernel.org/stable/c/09ea3eb9a518565f5bca386e81b993ed8825f5e8" } ], "title": "nfsd: fix clock domain mismatch in clients_still_reclaiming()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-89685", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:25:59.702339Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:48.681Z" } } ] } }