CVE-2026-89660

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89660", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.744Z", "datePublished": "2026-09-11T19:45:48.341Z", "dateUpdated": "2026-10-19T08:50:31.845Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:31.845Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during admin state revocation\n\nA stateid holds only a bare pointer to its nfs4_client; a stateid\nreference does not pin it. The client survives only because\n__destroy_client() drains its stateids before free_client() runs.\n\nnfsd4_revoke_states() drops nn->client_lock across revoke_one_stid(),\nwhich dereferences the client to revoke a stateid and read\nclp->cl_minorversion. A teardown racing the dropped lock can free\nthe client first.\n\nPinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and\nEXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero.\nforce_expire_client() ignores it: once its wait for cl_rpc_users to\nreach zero has passed, a later pin goes unnoticed.\n\nUnder client_lock, skip a client whose cl_time is already zero --\nforce_expire_client() clears it there before waiting -- otherwise pin\ncl_rpc_users before dropping the lock. The walk then either sees the\nexpiry and skips, or pins in time for that wait to cover the revoke."}], "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 UAF is in nfsd nfsd4_revoke_states(). A remote NFSv4 peer reaches the racing expire_client() over TCP/2049 via EXCHANGE_ID/CREATE_SESSION, SETCLIENTID_CONFIRM, or DESTROY_CLIENTID (ALLOWED_WITHOUT_FH), which free nfs4_client while the revoke walk still dereferences it.\nAC:L - The attacker controls the teardown side: they hold many stateids so the revoke walk drops client_lock once per stid, and concurrently retry EXCHANGE_ID/CREATE_SESSION or SETCLIENTID_CONFIRM so mark_client_expired_locked() succeeds while cl_rpc_users is unpinned.\nPR:N - EXCHANGE_ID, CREATE_SESSION, SETCLIENTID, SETCLIENTID_CONFIRM, and DESTROY_CLIENTID are ALLOWED_WITHOUT_FH with no export check. Typical AUTH_SYS/AUTH_NULL nfsd deployments do not verify RPC credentials, so any host that can reach TCP/2049 can establish state and trigger expire.\nUI:N - The attacker drives the NFS compounds that create state and expire the client. Administrative unlock_filesystem/unexport is a server operational condition (unexport or response to a misbehaving client), not a required victim user action.\nS:U - The freed object is struct nfs4_client in the NFS server kernel. Impact remains in that kernel security authority; there is no VM, IOMMU, or sandbox boundary crossing.\nC:H - revoke_one_stid() and the subsequent clp->cl_minorversion read dereference nfs4_client after free_client() kmem_cache_free's the mergeable client_slab object (KMEM_CACHE flags 0). Reclaim via EXCHANGE_ID discloses kernel memory; a UAF is C:H.\nI:H - revoke_one_stid() takes cl_lock and nfs4_put_stid() does refcount_dec_and_lock/idr_remove on the freed client's cl_lock/cl_stateids, concurrent with __destroy_client(), a slab UAF write primitive for heap corruption and control-flow hijacking.\nA:H - Use-after-free of nfs4_client in the nfsd revoke path oopses or panics the NFS server even without full exploitation, fully denying service of the host."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfs4state.c"], "versions": [{"version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "lessThan": "e1ba4d3c5bfdca3f013b8cbc829ae2f7975d8608", "status": "affected", "versionType": "git"}, {"version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "lessThan": "549bd9868e9d77b07ea94870940d64342829c6ad", "status": "affected", "versionType": "git"}, {"version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "lessThan": "bf1f948691523282cc4905bc6cd325e0c0b49e6a", "status": "affected", "versionType": "git"}, {"version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "lessThan": "e270e5a0778e5bff852c8862ce9576ce70359393", "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/nfs4state.c"], "versions": [{"version": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "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": "6.9", "versionEndExcluding": "6.12.111"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.51"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/e1ba4d3c5bfdca3f013b8cbc829ae2f7975d8608"}, {"url": "https://git.kernel.org/stable/c/549bd9868e9d77b07ea94870940d64342829c6ad"}, {"url": "https://git.kernel.org/stable/c/bf1f948691523282cc4905bc6cd325e0c0b49e6a"}, {"url": "https://git.kernel.org/stable/c/e270e5a0778e5bff852c8862ce9576ce70359393"}], "title": "NFSD: Prevent client use-after-free during admin state revocation", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4state.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "e1ba4d3c5bfdca3f013b8cbc829ae2f7975d8608", "status": "affected", "version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "versionType": "git"}, {"lessThan": "549bd9868e9d77b07ea94870940d64342829c6ad", "status": "affected", "version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "versionType": "git"}, {"lessThan": "bf1f948691523282cc4905bc6cd325e0c0b49e6a", "status": "affected", "version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "versionType": "git"}, {"lessThan": "e270e5a0778e5bff852c8862ce9576ce70359393", "status": "affected", "version": "1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4state.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.9"}, {"lessThan": "6.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.111", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.51", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "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 client use-after-free during admin state revocation\n\nA stateid holds only a bare pointer to its nfs4_client; a stateid\nreference does not pin it. The client survives only because\n__destroy_client() drains its stateids before free_client() runs.\n\nnfsd4_revoke_states() drops nn->client_lock across revoke_one_stid(),\nwhich dereferences the client to revoke a stateid and read\nclp->cl_minorversion. A teardown racing the dropped lock can free\nthe client first.\n\nPinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and\nEXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero.\nforce_expire_client() ignores it: once its wait for cl_rpc_users to\nreach zero has passed, a later pin goes unnoticed.\n\nUnder client_lock, skip a client whose cl_time is already zero --\nforce_expire_client() clears it there before waiting -- otherwise pin\ncl_rpc_users before dropping the lock. The walk then either sees the\nexpiry and skips, or pins in time for that wait to cover the revoke."}], "id": "CVE-2026-89660", "lastModified": "2026-10-19T09:18:03.880", "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"}]}, "published": "2026-09-11T20:19:52.300", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/549bd9868e9d77b07ea94870940d64342829c6ad"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bf1f948691523282cc4905bc6cd325e0c0b49e6a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e1ba4d3c5bfdca3f013b8cbc829ae2f7975d8608"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e270e5a0778e5bff852c8862ce9576ce70359393"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: NFSD use-after-free during client state revocation", "id": "2532092", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532092"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's Network File System Daemon (NFSD). This vulnerability, a use-after-free, occurs during the revocation of client administrative states. A race condition can allow a client's memory to be freed prematurely while still being referenced, potentially leading to system instability or a denial of service. In some scenarios, this type of memory corruption could be exploited by a remote attacker to achieve arbitrary code execution."], "name": "CVE-2026-89660", "package_state": [{"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-11T19:45:48Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89660\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89660\nhttps://git.kernel.org/stable/c/549bd9868e9d77b07ea94870940d64342829c6ad\nhttps://git.kernel.org/stable/c/bf1f948691523282cc4905bc6cd325e0c0b49e6a\nhttps://git.kernel.org/stable/c/e270e5a0778e5bff852c8862ce9576ce70359393"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc,549bd9868e9d77b07ea94870940d64342829c6ad)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc,bf1f948691523282cc4905bc6cd325e0c0b49e6a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc,e270e5a0778e5bff852c8862ce9576ce70359393)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.51,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T06:15:04.246651+00:00", "updated": "2026-09-15T21:00:17.848680+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}