{"id":"CVE-2026-89711","revision":"a38572c0d746423c8bb0ea1caa6a7753","records":[{"revision":"a38572c0d746423c8bb0ea1caa6a7753","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89711","aliases":[],"title":"NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check","description":"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.","state":0,"publishedAt":"2026-09-11T19:46:26.269+00:00","modifiedAt":"2026-10-19T08:51:24.221+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfsfh.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"ae251937c6f0237e5b555a5e4ba4595b8206e865\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"e145e8d67a5d41c72d322e7f87ab474d39d9dfb7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"9f4434893a2783f7384d993cea883aff3fb7a52d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"2ef131323999539038e306773c8256403834361b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"b55b4d880bb080fa10eb08ba21a5d8679b8102fe\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"7ef182a8fe9c12b0d936880b1e504840639aa009\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"a275de3bac5635514ca830f2e46b5ff0e66b5c4c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c\",\n                            \"lessThan\": \"aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfsfh.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","score":8.2,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/ae251937c6f0237e5b555a5e4ba4595b8206e865","https://git.kernel.org/stable/c/e145e8d67a5d41c72d322e7f87ab474d39d9dfb7","https://git.kernel.org/stable/c/9f4434893a2783f7384d993cea883aff3fb7a52d","https://git.kernel.org/stable/c/2ef131323999539038e306773c8256403834361b","https://git.kernel.org/stable/c/b55b4d880bb080fa10eb08ba21a5d8679b8102fe","https://git.kernel.org/stable/c/7ef182a8fe9c12b0d936880b1e504840639aa009","https://git.kernel.org/stable/c/a275de3bac5635514ca830f2e46b5ff0e66b5c4c","https://git.kernel.org/stable/c/aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89711","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89711","identifiers":["CVE-2026-89711"]},"retained":false,"historicalAffected":[]}],"coverage":[]}