CVE-2026-89679

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89679", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.747Z", "datePublished": "2026-09-11T19:46:02.833Z", "dateUpdated": "2026-10-19T08:50:52.556Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:52.556Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs\n\nWhen a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or\nFATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr()\nsets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate\nthe stateid.\n\nIf the client supplies the NFSv4 \"one stateid\" (all-0xFF bytes),\ncheck_special_stateids() returns nfs_ok without populating the output\nnfs4_stid pointer, because the special-stateid path in\nnfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the\n\"if (s)\" block that would set *cstid is skipped. The local variable `st`\nremains NULL.\n\nBack in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally\ndereferences st->sc_type (at offset 4 from NULL), causing a kernel oops.\n\nThis is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH,\nSETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})].\nNo authentication, delegation, or prior state is required.\n\nFix by adding a NULL check before the dereference. A special stateid is\nnot a delegation stateid, so the existing nfserr_bad_stateid return value\nis already correct; we only need to guard the pointer dereference itself."}], "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 is the in-kernel NFSv4 server; nfsd4_setattr() is reached from NFSPROC4_COMPOUND over TCP/2049. A remote peer triggers it with PUTROOTFH then SETATTR; no local access to the server is required.\nAC:L - COMPOUND [PUTROOTFH, SETATTR(ONE_STATEID, FATTR4_WORD2_TIME_DELEG_ACCESS)] makes check_special_stateids() return nfs_ok with st still NULL, then nfsd4_setattr() unconditionally reads st->sc_type. The crash is deterministic; no race, special layout, or rare config is required.\nPR:N - The NULL deref runs in nfsd4_setattr() before nfsd_setattr()/nfsd_permission and needs no NFSv4 session, delegation, or prior state (v4.0 COMPOUND). Default AUTH_SYS/AUTH_NULL credentials are self-asserted, so any host that can reach the NFS port can trigger it.\nUI:N - The attacker sends the crafted NFSv4 COMPOUND themselves; no victim must mount an export, open a file, or otherwise interact.\nS:U - The NULL dereference oopses an nfsd thread on the NFS server. Impact stays inside that kernel's security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - This is a pure NULL-pointer read of st->sc_type at offset 4 from NULL. It oopses without leaking kernel memory or providing an information-disclosure primitive.\nI:N - The bug only reads through a NULL nfs4_stid pointer; it does not write memory, corrupt adjacent objects, or yield a control-flow hijack. A remote NFS client cannot map the NULL page.\nA:H - The NULL dereference causes a kernel oops in the nfsd thread. Repeated requests can exhaust nfsd threads or panic the host (panic_on_oops), denying NFS service and taking down the server."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfs4proc.c"], "versions": [{"version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "lessThan": "3c5119b799a7f57db332b2c31e806de16c869f0f", "status": "affected", "versionType": "git"}, {"version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "lessThan": "3c896db123892256fd39af0ee8c2d02c63539983", "status": "affected", "versionType": "git"}, {"version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "lessThan": "fe456c8c0931bb3e8a03d429920e87fd85747fba", "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/nfs4proc.c"], "versions": [{"version": "6.14", "status": "affected"}, {"version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "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": "6.14", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3c5119b799a7f57db332b2c31e806de16c869f0f"}, {"url": "https://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983"}, {"url": "https://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba"}], "title": "nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4proc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "3c5119b799a7f57db332b2c31e806de16c869f0f", "status": "affected", "version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "versionType": "git"}, {"lessThan": "3c896db123892256fd39af0ee8c2d02c63539983", "status": "affected", "version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "versionType": "git"}, {"lessThan": "fe456c8c0931bb3e8a03d429920e87fd85747fba", "status": "affected", "version": "7e13f4f8d27dc02fb88666f603c53ca749d56f92", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4proc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.14"}, {"lessThan": "6.14", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "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: fix null dereference in nfsd4_setattr for deleg timestamp attrs\n\nWhen a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or\nFATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr()\nsets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate\nthe stateid.\n\nIf the client supplies the NFSv4 \"one stateid\" (all-0xFF bytes),\ncheck_special_stateids() returns nfs_ok without populating the output\nnfs4_stid pointer, because the special-stateid path in\nnfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the\n\"if (s)\" block that would set *cstid is skipped. The local variable `st`\nremains NULL.\n\nBack in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally\ndereferences st->sc_type (at offset 4 from NULL), causing a kernel oops.\n\nThis is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH,\nSETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})].\nNo authentication, delegation, or prior state is required.\n\nFix by adding a NULL check before the dereference. A special stateid is\nnot a delegation stateid, so the existing nfserr_bad_stateid return value\nis already correct; we only need to guard the pointer dereference itself."}], "id": "CVE-2026-89679", "lastModified": "2026-10-19T09:18:06.220", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:19:54.660", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3c5119b799a7f57db332b2c31e806de16c869f0f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel nfsd: Denial of Service via specially crafted SETATTR request", "id": "2532085", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532085"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["A flaw was found in the Linux kernel's nfsd component. A remote attacker can exploit this by sending a specially crafted SETATTR request that includes specific delegation timestamp attributes and a special NFSv4 state ID. This triggers a null dereference, leading to a kernel crash and a Denial of Service (DoS). No authentication is required for a successful attack."], "name": "CVE-2026-89679", "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": "2026-09-11T19:46:02Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89679\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89679\nhttps://git.kernel.org/stable/c/3c5119b799a7f57db332b2c31e806de16c869f0f\nhttps://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983\nhttps://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7e13f4f8d27dc02fb88666f603c53ca749d56f92,3c5119b799a7f57db332b2c31e806de16c869f0f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7e13f4f8d27dc02fb88666f603c53ca749d56f92,3c896db123892256fd39af0ee8c2d02c63539983)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7e13f4f8d27dc02fb88666f603c53ca749d56f92,fe456c8c0931bb3e8a03d429920e87fd85747fba)"}}], "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": "[6.14,6.14]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.14)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.50,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.4,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "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": "2026-09-12T05:45:09.505837+00:00", "updated": "2026-09-15T20:30:10.335014+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}