{"id":"CVE-2026-89674","revision":"4b597f4fc58944ff9014fc9369cfd9b0","records":[{"revision":"4b597f4fc58944ff9014fc9369cfd9b0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89674","aliases":[],"title":"nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget\n\nThe XDR buffer size calculation in nfsd4_ff_encode_layoutget() has\nmultiple errors that can result in either an out-of-bounds write or\nleaking uninitialized kernel memory to the client:\n\n - fh_len doesn't account for XDR padding on the file handle data\n - uid and gid lengths use \"8 + len\" but xdr_encode_opaque() actually\n writes \"4 + xdr_align_size(len)\" bytes\n - ds_len omits the flags and stats_collect_hint fields (8 bytes),\n while len's header constant overestimates by 8 bytes -- these\n partially cancel but leave a net mismatch\n\nThe worst case occurs with short strings (e.g. uid=0, gid=0 with an\nodd-sized file handle), where the function writes up to 5 bytes past\nthe reserved XDR buffer. Conversely, when string lengths happen to be\n4-byte aligned, the reservation is too large and stale buffer content\nis sent to the client.\n\nFix this by breaking out every encoded field explicitly in the ds_len\ncalculation, using xdr_align_size() for all variable-length opaque\nfields, and correcting the header constants.","state":0,"publishedAt":"2026-09-11T19:45:58.883+00:00","modifiedAt":"2026-10-19T08:50:47.609+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/flexfilelayoutxdr.c\"\n ],\n \"versions\": [\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"3a7fd224df0fbb42167eb1b77be45d72fe0b1098\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"29e4478e2ed5a227e8f0c33cacb91bf227cedd47\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"65a72b721943618eeb3a41c8b36e915591f3f83f\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"bee826c00ac900473f91306f1f3e5a5a81fd4a74\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"e7d9d23ecd9172f05b09bb678ff22db8e361c428\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"0380129b1373c437eb35401a174671c8888f4b80\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"c81cef6a805dec266c10fc4f83c93d6fcf1a2b43\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9b9960a0ca4773e21c4b153ed355583946346b25\",\n \"lessThan\": \"f9868174af49d207fbaf0c5e055d088a983684af\",\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/flexfilelayoutxdr.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:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/3a7fd224df0fbb42167eb1b77be45d72fe0b1098","https://git.kernel.org/stable/c/29e4478e2ed5a227e8f0c33cacb91bf227cedd47","https://git.kernel.org/stable/c/65a72b721943618eeb3a41c8b36e915591f3f83f","https://git.kernel.org/stable/c/bee826c00ac900473f91306f1f3e5a5a81fd4a74","https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428","https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80","https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43","https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89674","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89674","identifiers":["CVE-2026-89674"]},"retained":false,"historicalAffected":[]}],"coverage":[]}