CVE-2026-89711

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89711", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.751Z", "datePublished": "2026-09-11T19:46:26.269Z", "dateUpdated": "2026-10-19T08:51:24.221Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:51:24.221Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check\n\nThe header for commit e75b23f9e323 (\"nfsd: check d_can_lookup in\nfh_verify of directories\") details the assumption that justified\nadding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is\ninvalid (in the case of NFS reexport).\n\nWhen NFSD exports an NFS filesystem it is very possible for\nnfsd_mode_check() to encounter a @dentry that doesn't have\ni_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and\nNFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).\n\nSo remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir\nreturn on that branch must stay. It guards the subsequent\nlookup_one_unlocked() -> __lookup_slow() path, which calls\ninode->i_op->lookup() with no NULL check, so returning nfserr_notdir\nis what keeps a client LOOKUP into such a @dentry from dereferencing\na NULL method pointer."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "baseScore": 8.2, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - nfsd is the in-kernel NFS server. A remote client reaches nfsd_mode_check() via directory ops (LOOKUP, CREATE, OPEN) over TCP/UDP 2049: svc_recv to nfsd_dispatch to fh_verify to __fh_verify.\nAC:L - On an nfsd host that reexports NFS, mountpoint and NFSv4 referral dentries lack i_op->lookup so d_can_lookup() is false. A client LOOKUP or other S_IFDIR fh_verify on that filehandle hits WARN_ON_ONCE deterministically with no race.\nPR:N - nfsd_mode_check() runs in __fh_verify() after filehandle decode but before check_security_flavor() and nfsd_permission(). Typical nfsd deployments accept AUTH_SYS/AUTH_NULL, so an unauthenticated peer that can reach the export triggers it with self-asserted credentials.\nUI:N - The attacker sends the NFS RPCs (NFSv4 PUTFH plus LOOKUP, or NFSv3 LOOKUP) themselves. No victim user must mount a filesystem, open a file, or otherwise interact.\nS:U - The WARN_ON_ONCE splat and any panic_on_warn crash remain inside the NFS server kernel. This is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:L - WARN_ON_ONCE calls __warn()/dump_stack(), disclosing kernel text addresses in dmesg. There is no use-after-free or out-of-bounds read; the path returns nfserr_notdir without copying kernel memory to the client.\nI:N - The fix only removes the warning. The existing nfserr_notdir return already blocks lookup_one_unlocked() from calling a NULL i_op->lookup, so there is no memory corruption, write primitive, or control-flow hijack.\nA:H - WARN_ON_ONCE taints the kernel and panics the host when panic_on_warn is enabled or warn_limit is exceeded, so a remote NFS client can deny service by operating on a reexported mountpoint or referral directory."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfsfh.c"], "versions": [{"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "ae251937c6f0237e5b555a5e4ba4595b8206e865", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "e145e8d67a5d41c72d322e7f87ab474d39d9dfb7", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "9f4434893a2783f7384d993cea883aff3fb7a52d", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "2ef131323999539038e306773c8256403834361b", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "b55b4d880bb080fa10eb08ba21a5d8679b8102fe", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "7ef182a8fe9c12b0d936880b1e504840639aa009", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "a275de3bac5635514ca830f2e46b5ff0e66b5c4c", "status": "affected", "versionType": "git"}, {"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e", "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/nfsfh.c"], "versions": [{"version": "4.8", "status": "affected"}, {"version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "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": "4.8", "versionEndExcluding": "5.10.270"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.221"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ae251937c6f0237e5b555a5e4ba4595b8206e865"}, {"url": "https://git.kernel.org/stable/c/e145e8d67a5d41c72d322e7f87ab474d39d9dfb7"}, {"url": "https://git.kernel.org/stable/c/9f4434893a2783f7384d993cea883aff3fb7a52d"}, {"url": "https://git.kernel.org/stable/c/2ef131323999539038e306773c8256403834361b"}, {"url": "https://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe"}, {"url": "https://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009"}, {"url": "https://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c"}, {"url": "https://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e"}], "title": "NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89711", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-16T19:26:26.232461Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:36:59.484Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89711", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-16T19:26:26.232461Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:27.009Z"}}], "cna": {"title": "NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 8.2, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - nfsd is the in-kernel NFS server. A remote client reaches nfsd_mode_check() via directory ops (LOOKUP, CREATE, OPEN) over TCP/UDP 2049: svc_recv to nfsd_dispatch to fh_verify to __fh_verify.\nAC:L - On an nfsd host that reexports NFS, mountpoint and NFSv4 referral dentries lack i_op->lookup so d_can_lookup() is false. A client LOOKUP or other S_IFDIR fh_verify on that filehandle hits WARN_ON_ONCE deterministically with no race.\nPR:N - nfsd_mode_check() runs in __fh_verify() after filehandle decode but before check_security_flavor() and nfsd_permission(). Typical nfsd deployments accept AUTH_SYS/AUTH_NULL, so an unauthenticated peer that can reach the export triggers it with self-asserted credentials.\nUI:N - The attacker sends the NFS RPCs (NFSv4 PUTFH plus LOOKUP, or NFSv3 LOOKUP) themselves. No victim user must mount a filesystem, open a file, or otherwise interact.\nS:U - The WARN_ON_ONCE splat and any panic_on_warn crash remain inside the NFS server kernel. This is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:L - WARN_ON_ONCE calls __warn()/dump_stack(), disclosing kernel text addresses in dmesg. There is no use-after-free or out-of-bounds read; the path returns nfserr_notdir without copying kernel memory to the client.\nI:N - The fix only removes the warning. The existing nfserr_notdir return already blocks lookup_one_unlocked() from calling a NULL i_op->lookup, so there is no memory corruption, write primitive, or control-flow hijack.\nA:H - WARN_ON_ONCE taints the kernel and panics the host when panic_on_warn is enabled or warn_limit is exceeded, so a remote NFS client can deny service by operating on a reexported mountpoint or referral directory."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "ae251937c6f0237e5b555a5e4ba4595b8206e865", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "e145e8d67a5d41c72d322e7f87ab474d39d9dfb7", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "9f4434893a2783f7384d993cea883aff3fb7a52d", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "2ef131323999539038e306773c8256403834361b", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "b55b4d880bb080fa10eb08ba21a5d8679b8102fe", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "7ef182a8fe9c12b0d936880b1e504840639aa009", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "a275de3bac5635514ca830f2e46b5ff0e66b5c4c", "versionType": "git"}, {"status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "lessThan": "aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e", "versionType": "git"}], "programFiles": ["fs/nfsd/nfsfh.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.8"}, {"status": "unaffected", "version": "0", "lessThan": "4.8", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.270", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.221", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.188", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.157", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.109", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.50", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.4", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/nfsd/nfsfh.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/ae251937c6f0237e5b555a5e4ba4595b8206e865"}, {"url": "https://git.kernel.org/stable/c/e145e8d67a5d41c72d322e7f87ab474d39d9dfb7"}, {"url": "https://git.kernel.org/stable/c/9f4434893a2783f7384d993cea883aff3fb7a52d"}, {"url": "https://git.kernel.org/stable/c/2ef131323999539038e306773c8256403834361b"}, {"url": "https://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe"}, {"url": "https://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009"}, {"url": "https://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c"}, {"url": "https://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check\n\nThe header for commit e75b23f9e323 (\"nfsd: check d_can_lookup in\nfh_verify of directories\") details the assumption that justified\nadding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is\ninvalid (in the case of NFS reexport).\n\nWhen NFSD exports an NFS filesystem it is very possible for\nnfsd_mode_check() to encounter a @dentry that doesn't have\ni_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and\nNFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).\n\nSo remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir\nreturn on that branch must stay. It guards the subsequent\nlookup_one_unlocked() -> __lookup_slow() path, which calls\ninode->i_op->lookup() with no NULL check, so returning nfserr_notdir\nis what keeps a client LOOKUP into such a @dentry from dereferencing\na NULL method pointer."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.270", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.221", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.188", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.157", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.109", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.50", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2.4", "versionStartIncluding": "4.8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.3", "versionStartIncluding": "4.8"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:51:24.221Z"}}}, "cveMetadata": {"cveId": "CVE-2026-89711", "state": "PUBLISHED", "dateUpdated": "2026-10-19T08:51:24.221Z", "dateReserved": "2026-09-11T19:38:34.751Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-09-11T19:46:26.269Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfsfh.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "ae251937c6f0237e5b555a5e4ba4595b8206e865", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "e145e8d67a5d41c72d322e7f87ab474d39d9dfb7", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "9f4434893a2783f7384d993cea883aff3fb7a52d", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "2ef131323999539038e306773c8256403834361b", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "b55b4d880bb080fa10eb08ba21a5d8679b8102fe", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "7ef182a8fe9c12b0d936880b1e504840639aa009", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "a275de3bac5635514ca830f2e46b5ff0e66b5c4c", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}, {"lessThan": "aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e", "status": "affected", "version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfsfh.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.8"}, {"lessThan": "4.8", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.270", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.221", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "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: remove flawed WARN_ON_ONCE from nfsd_mode_check\n\nThe header for commit e75b23f9e323 (\"nfsd: check d_can_lookup in\nfh_verify of directories\") details the assumption that justified\nadding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is\ninvalid (in the case of NFS reexport).\n\nWhen NFSD exports an NFS filesystem it is very possible for\nnfsd_mode_check() to encounter a @dentry that doesn't have\ni_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and\nNFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).\n\nSo remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir\nreturn on that branch must stay. It guards the subsequent\nlookup_one_unlocked() -> __lookup_slow() path, which calls\ninode->i_op->lookup() with no NULL check, so returning nfserr_notdir\nis what keeps a client LOOKUP into such a @dentry from dereferencing\na NULL method pointer."}], "id": "CVE-2026-89711", "lastModified": "2026-10-19T09:18:09.960", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-89711", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T19:26:26.232461Z", "version": "2.0.3"}}]}, "published": "2026-09-11T20:19:58.500", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2ef131323999539038e306773c8256403834361b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9f4434893a2783f7384d993cea883aff3fb7a52d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ae251937c6f0237e5b555a5e4ba4595b8206e865"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e145e8d67a5d41c72d322e7f87ab474d39d9dfb7"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: NFSD null pointer dereference via NFS reexport", "id": "2532508", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532508"}, "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 Network File System Daemon (NFSD). An invalid assumption in the `nfsd_mode_check()` function regarding directory lookup capabilities during NFS reexport could lead to a null pointer dereference. A remote attacker could exploit this by performing a LOOKUP operation on a specially crafted NFS reexport, potentially causing a system crash and resulting in a Denial of Service (DoS)."], "name": "CVE-2026-89711", "public_date": "2026-09-11T19:46:26Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89711\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89711\nhttps://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009\nhttps://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c\nhttps://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e\nhttps://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,b55b4d880bb080fa10eb08ba21a5d8679b8102fe)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,7ef182a8fe9c12b0d936880b1e504840639aa009)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,a275de3bac5635514ca830f2e46b5ff0e66b5c4c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e)"}}], "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": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,b55b4d880bb080fa10eb08ba21a5d8679b8102fe)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,7ef182a8fe9c12b0d936880b1e504840639aa009)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,a275de3bac5635514ca830f2e46b5ff0e66b5c4c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c,aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.8"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,4.8)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.12.109,6.12.*]"}}, {"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": "2026-09-12T12:30:14.594991+00:00", "updated": "2026-09-15T19:30:12.153056+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}