{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89661", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.744Z", "datePublished": "2026-09-11T19:45:49.086Z", "dateUpdated": "2026-09-11T19:45:49.086Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-11T19:45:49.086Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent post-shutdown use-after-free in unlock_filesystem\n\nWriting a filesystem path to /proc/fs/nfsd/unlock_filesystem runs\nnfsd4_cancel_copy_by_sb() before nfsd_mutex is held and before the\nhandler confirms that nn->nfsd_serv is set. Once nfsd has shut down,\nnfs4_state_destroy_net() has freed nn->conf_id_hashtbl but left the\npointer intact, so the cancel helper iterates freed slab memory as an\narray of struct list_head and then dereferences a bogus nfs4_client\nwhen it takes clp->async_lock. A local administrator holding\nCAP_SYS_ADMIN can reach this use-after-free by stopping the server and\nthen writing to unlock_filesystem; KASAN reports a slab-use-after-free\nread in nfsd4_cancel_copy_by_sb().\n\nnfsd4_revoke_states() walks the same state tables and for that reason\nalready runs only under nfsd_mutex with nn->nfsd_serv confirmed\npresent. Move the async COPY cancel into that protected section so\nevery NFSv4 state-table walker on this path observes a running server.\nAsync copies exist only while the server runs, so gating the cancel on\nnn->nfsd_serv loses nothing."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfsctl.c"], "versions": [{"version": "3daab3112f039cf849f96764019b096bb0a39d04", "lessThan": "0c1a755b7212e0835398d4df5e782ea85ccd7476", "status": "affected", "versionType": "git"}, {"version": "3daab3112f039cf849f96764019b096bb0a39d04", "lessThan": "292d915d3ba6fd15eeb88351fa10581683073109", "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/nfsctl.c"], "versions": [{"version": "7.0", "status": "affected"}, {"version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc1", "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": "7.0", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.3-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0c1a755b7212e0835398d4df5e782ea85ccd7476"}, {"url": "https://git.kernel.org/stable/c/292d915d3ba6fd15eeb88351fa10581683073109"}], "title": "NFSD: Prevent post-shutdown use-after-free in unlock_filesystem", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfsctl.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "0c1a755b7212e0835398d4df5e782ea85ccd7476", "status": "affected", "version": "3daab3112f039cf849f96764019b096bb0a39d04", "versionType": "git"}, {"lessThan": "292d915d3ba6fd15eeb88351fa10581683073109", "status": "affected", "version": "3daab3112f039cf849f96764019b096bb0a39d04", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfsctl.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.0"}, {"lessThan": "7.0", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent post-shutdown use-after-free in unlock_filesystem\n\nWriting a filesystem path to /proc/fs/nfsd/unlock_filesystem runs\nnfsd4_cancel_copy_by_sb() before nfsd_mutex is held and before the\nhandler confirms that nn->nfsd_serv is set. Once nfsd has shut down,\nnfs4_state_destroy_net() has freed nn->conf_id_hashtbl but left the\npointer intact, so the cancel helper iterates freed slab memory as an\narray of struct list_head and then dereferences a bogus nfs4_client\nwhen it takes clp->async_lock. A local administrator holding\nCAP_SYS_ADMIN can reach this use-after-free by stopping the server and\nthen writing to unlock_filesystem; KASAN reports a slab-use-after-free\nread in nfsd4_cancel_copy_by_sb().\n\nnfsd4_revoke_states() walks the same state tables and for that reason\nalready runs only under nfsd_mutex with nn->nfsd_serv confirmed\npresent. Move the async COPY cancel into that protected section so\nevery NFSv4 state-table walker on this path observes a running server.\nAsync copies exist only while the server runs, so gating the cancel on\nnn->nfsd_serv loses nothing."}], "id": "CVE-2026-89661", "lastModified": "2026-09-11T20:19:52.413", "metrics": {}, "published": "2026-09-11T20:19:52.413", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0c1a755b7212e0835398d4df5e782ea85ccd7476"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/292d915d3ba6fd15eeb88351fa10581683073109"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux Kernel: Use-after-free in NFSD can lead to denial of service", "id": "2532346", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532346"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's Network File System Daemon (NFSD). A local administrator with CAP_SYS_ADMIN capabilities can trigger a use-after-free vulnerability by writing to /proc/fs/nfsd/unlock_filesystem after the NFSD server has shut down. This can lead to memory corruption, potentially causing a denial of service."], "name": "CVE-2026-89661", "public_date": "2026-09-11T19:45:49Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89661\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89661\nhttps://git.kernel.org/stable/c/0c1a755b7212e0835398d4df5e782ea85ccd7476\nhttps://git.kernel.org/stable/c/292d915d3ba6fd15eeb88351fa10581683073109"], "threat_severity": "Important"}

{"created": "2026-09-12T04:45:07.679421+00:00", "updated": "2026-09-12T21:30:17.106972+00:00", "vendors": []}