{"id":"CVE-2026-89665","revision":"d59042f7f587416fb019b70103a30bc0","records":[{"revision":"d59042f7f587416fb019b70103a30bc0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89665","aliases":[],"title":"nfsd: reject out-of-range useconds in NFSv2 SETATTR/CREATE","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reject out-of-range useconds in NFSv2 SETATTR/CREATE\n\nThe NFSv2 sattr decoder converts the wire useconds to nanoseconds in\nsvcxdr_decode_sattr():\n\n\tiap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;\n\ntmp2 is a u32 and NSEC_PER_USEC is 1000, so the product is computed in\nunsigned long. On ILP32 that is 32 bits, and an out-of-range useconds\nvalue such as 4294968 wraps to tv_nsec == 704. The corruption therefore\nhappens during decode, before any proc function can inspect the value,\nand a later range check on tv_nsec would see an in-range result and\naccept it. Rejecting in the decoder yields an RPC GARBAGE_ARGS reply.\nNFSv2 defines no NFSERR_INVAL, so there is no NFS-level status to return\nfor a malformed time argument, and the check cannot move to the proc\nfunction the way the v3/v4 nsec range checks do.\n\nGuard the raw useconds before the multiplication and reject values\ngreater than 1000000. useconds == 1000000 is kept: it is the Sun\nconvention for \"set to the current server time\", and the in-tree Linux\nNFSv2 client emits it in both the atime and the mtime field for a plain\ntouch / utimes(file, NULL) (see encode_sattr() and\nxdr_encode_current_server_time() in fs/nfs/nfs2xdr.c). Rejecting 1000000\nwould turn that common operation into a hard decode failure for both\nSETATTR and CREATE. 1000000 * NSEC_PER_USEC is 10^9, which does not wrap\non ILP32, so the Sun convention value passes through safely. Only\ngenuinely out-of-range values (> 1000000) are rejected. The atime and\nmtime guards are therefore symmetric.\n\nThe decoder only applied the Sun convention in the mtime block, which\nclears ATTR_ATIME_SET|ATTR_MTIME_SET when mtime useconds == 1000000. If a\nclient puts 1000000 in the atime field but not in the mtime field, the\natime block stored an out-of-range tv_nsec (10^9) and left ATTR_ATIME_SET\nset, so the bogus value reached the filesystem. Apply the convention in\nthe atime block as well, clearing ATTR_ATIME_SET so the server uses its\ncurrent time and ignores the value. Only ATTR_ATIME_SET is cleared there.\nThe mtime block keeps its existing behavior, where 1000000 means \"set\nboth atime and mtime to now\".\n\n[ cel: various tweaks, addenda, and clean-ups ]","state":0,"publishedAt":"2026-09-11T19:45:52.102+00:00","modifiedAt":"2026-10-19T08:50:36.772+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/nfsxdr.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"cdc3299f7072777b09c9582a3b8b65bb163ddcf3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"09a79d9ab35a39603c834e8f6333603292f9c816\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"5296a2442d12d45d6eea7b4d3ec3ffecc1821cac\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"1db456ffc22e045f49f7b9e62415a26b3f33f200\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"a937dd1aa2d92291fe0a1860d17e90d8f206cd22\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"ad02d095439f89cbd6629420c7e3ba476457b83b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"1195483965a5f63d2dde18054ec7e50a23b9071c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"26709c8ffe73772eb69e68d553ac71d91228dccc\",\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/nfsxdr.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.12\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.12\",\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:N/I:H/A:L","score":8.2,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/cdc3299f7072777b09c9582a3b8b65bb163ddcf3","https://git.kernel.org/stable/c/09a79d9ab35a39603c834e8f6333603292f9c816","https://git.kernel.org/stable/c/5296a2442d12d45d6eea7b4d3ec3ffecc1821cac","https://git.kernel.org/stable/c/1db456ffc22e045f49f7b9e62415a26b3f33f200","https://git.kernel.org/stable/c/a937dd1aa2d92291fe0a1860d17e90d8f206cd22","https://git.kernel.org/stable/c/ad02d095439f89cbd6629420c7e3ba476457b83b","https://git.kernel.org/stable/c/1195483965a5f63d2dde18054ec7e50a23b9071c","https://git.kernel.org/stable/c/26709c8ffe73772eb69e68d553ac71d91228dccc"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89665","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89665","identifiers":["CVE-2026-89665"]},"retained":false,"historicalAffected":[]}],"coverage":[]}