CVE-2026-89691

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89691", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.749Z", "datePublished": "2026-09-11T19:46:11.284Z", "dateUpdated": "2026-10-19T08:51:04.497Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:51:04.497Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: clear opcnt on compound arg release to prevent OOB read\n\nnfsd4_release_compoundargs() resets args->ops to the inline iops[8]\narray when the dynamically-allocated ops buffer is freed, but leaves\nargs->opcnt at its original value (which can be up to 200 for NFSv4.1+\ncompounds).\n\nIf rq_status_counter is stuck at an odd value (which can happen when\nnfsd_dispatch() hits an error path after setting it odd), the RPC\nstatus dumpit handler reads min(opcnt, 16) entries from args->ops[].\nSince iops only has 8 elements and is the last field in struct\nnfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory\nand leaks it to userspace via netlink.\n\nZero opcnt unconditionally in nfsd4_release_compoundargs() so stale\ncompound metadata is never exposed through the status interface.\n\n[ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The out-of-bounds read is in nfsd_nl_rpc_status_get_dumpit(), reached only via NFSD_CMD_RPC_STATUS_GET over AF_NETLINK. Remote NFSv4 compounds can leave stale opcnt after nfsd4_release_compoundargs() but never enter dumpit, so exploitation requires local netlink access.\nAC:L - The attacker can send an NFSv4.0 COMPOUND with more than eight ops including OP_CACHEME SETCLIENTID, then a duplicate in-flight RPC so nfsd_cache_lookup() returns RC_DROPIT and leaves rq_status_counter odd. Dumpit then deterministically reads min(opcnt,16) slots from the eight-element iops array; both sides are attacker-controlled.\nPR:L - NFSD_CMD_RPC_STATUS_GET is registered with GENL_CMD_CAP_DUMP and no GENL_ADMIN_PERM, so any unprivileged process in the nfsd network namespace can invoke the dump. Exploitation does not require CAP_NET_ADMIN or init-namespace root.\nUI:N - The attacker issues the netlink dump and the NFSv4 compounds themselves. No separate victim action such as mounting a filesystem or opening a device is required.\nS:U - The slab over-read and netlink leak occur in host-kernel nfsd on the local machine. Impact stays inside one security authority and is not a VM escape, IOMMU bypass, or other cross-boundary breakout.\nC:H - After release, dumpit reads args->ops[8..15].opnum past the trailing iops[8] array in nfsd4_compoundargs and returns those eight u32s via NFSD_A_RPC_STATUS_COMPOUND_OPS. That adjacent-slab out-of-bounds read is Confidentiality High unless limited to a few bytes.\nI:N - dumpit only loads opnum into a stack nfsd_genl_rqstp for netlink. There is no out-of-bounds write, use-after-free, or control-flow hijack primitive.\nA:H - Slots 8-15 are sampled at sizeof(struct nfsd4_op) stride past the kmalloc'd nfsd4_compoundargs object into adjacent or unmapped slab pages, which can oops the dumpit path even if the leak is not turned into a stable read."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfs4xdr.c"], "versions": [{"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "lessThan": "58bcdfb2b2e412088839ae740b1a95154dc0b8d0", "status": "affected", "versionType": "git"}, {"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "lessThan": "e879148867bd4c4cac42e063ffaffa187dddc6fe", "status": "affected", "versionType": "git"}, {"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "lessThan": "c1a4f7b1848f95302df598217e1c7a1410c2d0c5", "status": "affected", "versionType": "git"}, {"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "lessThan": "ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a", "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/nfs4xdr.c"], "versions": [{"version": "6.7", "status": "affected"}, {"version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "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": "6.7", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0"}, {"url": "https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"}, {"url": "https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5"}, {"url": "https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"}], "title": "nfsd: clear opcnt on compound arg release to prevent OOB read", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4xdr.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "58bcdfb2b2e412088839ae740b1a95154dc0b8d0", "status": "affected", "version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "versionType": "git"}, {"lessThan": "e879148867bd4c4cac42e063ffaffa187dddc6fe", "status": "affected", "version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "versionType": "git"}, {"lessThan": "c1a4f7b1848f95302df598217e1c7a1410c2d0c5", "status": "affected", "version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "versionType": "git"}, {"lessThan": "ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a", "status": "affected", "version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4xdr.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.7"}, {"lessThan": "6.7", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "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: clear opcnt on compound arg release to prevent OOB read\n\nnfsd4_release_compoundargs() resets args->ops to the inline iops[8]\narray when the dynamically-allocated ops buffer is freed, but leaves\nargs->opcnt at its original value (which can be up to 200 for NFSv4.1+\ncompounds).\n\nIf rq_status_counter is stuck at an odd value (which can happen when\nnfsd_dispatch() hits an error path after setting it odd), the RPC\nstatus dumpit handler reads min(opcnt, 16) entries from args->ops[].\nSince iops only has 8 elements and is the last field in struct\nnfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory\nand leaks it to userspace via netlink.\n\nZero opcnt unconditionally in nfsd4_release_compoundargs() so stale\ncompound metadata is never exposed through the status interface.\n\n[ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]"}], "id": "CVE-2026-89691", "lastModified": "2026-10-19T09:18:07.617", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:19:56.147", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux Kernel nfsd: Information disclosure via out-of-bounds read in compound argument release", "id": "2532399", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532399"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H", "status": "draft"}, "cwe": "CWE-125", "details": ["A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. The nfsd4_release_compoundargs() function does not properly clear an internal counter (opcnt) when releasing a buffer. This oversight can lead to an out-of-bounds read, allowing an attacker to access adjacent memory and potentially leak sensitive information to userspace through netlink."], "name": "CVE-2026-89691", "public_date": "2026-09-11T19:46:11Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89691\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89691\nhttps://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0\nhttps://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a\nhttps://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5\nhttps://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[bd9d6a3efa9709e653aafbeb859289feccb8e70c,58bcdfb2b2e412088839ae740b1a95154dc0b8d0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[bd9d6a3efa9709e653aafbeb859289feccb8e70c,e879148867bd4c4cac42e063ffaffa187dddc6fe)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[bd9d6a3efa9709e653aafbeb859289feccb8e70c,c1a4f7b1848f95302df598217e1c7a1410c2d0c5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[bd9d6a3efa9709e653aafbeb859289feccb8e70c,ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a)"}}], "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": "semver", "value": "6.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"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": "2026-09-12T08:15:07.027031+00:00", "updated": "2026-09-15T20:30:10.330373+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}