{"api_version":"1","generated_at":"2026-09-12T04:34:23+00:00","cve":"CVE-2026-89674","urls":{"html":"https://cve.report/CVE-2026-89674","api":"https://cve.report/api/cve/CVE-2026-89674.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89674","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89674"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:54","updated_at":"2026-09-11 20:19:54"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af","name":"https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43","name":"https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80","name":"https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428","name":"https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89674","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89674","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9b9960a0ca4773e21c4b153ed355583946346b25 e7d9d23ecd9172f05b09bb678ff22db8e361c428 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9b9960a0ca4773e21c4b153ed355583946346b25 0380129b1373c437eb35401a174671c8888f4b80 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9b9960a0ca4773e21c4b153ed355583946346b25 c81cef6a805dec266c10fc4f83c93d6fcf1a2b43 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9b9960a0ca4773e21c4b153ed355583946346b25 f9868174af49d207fbaf0c5e055d088a983684af git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.8","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.8 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/nfsd/flexfilelayoutxdr.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e7d9d23ecd9172f05b09bb678ff22db8e361c428","status":"affected","version":"9b9960a0ca4773e21c4b153ed355583946346b25","versionType":"git"},{"lessThan":"0380129b1373c437eb35401a174671c8888f4b80","status":"affected","version":"9b9960a0ca4773e21c4b153ed355583946346b25","versionType":"git"},{"lessThan":"c81cef6a805dec266c10fc4f83c93d6fcf1a2b43","status":"affected","version":"9b9960a0ca4773e21c4b153ed355583946346b25","versionType":"git"},{"lessThan":"f9868174af49d207fbaf0c5e055d088a983684af","status":"affected","version":"9b9960a0ca4773e21c4b153ed355583946346b25","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/nfsd/flexfilelayoutxdr.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":"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-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"4.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"4.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"4.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"4.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-09-11T19:45:58.883Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e7d9d23ecd9172f05b09bb678ff22db8e361c428"},{"url":"https://git.kernel.org/stable/c/0380129b1373c437eb35401a174671c8888f4b80"},{"url":"https://git.kernel.org/stable/c/c81cef6a805dec266c10fc4f83c93d6fcf1a2b43"},{"url":"https://git.kernel.org/stable/c/f9868174af49d207fbaf0c5e055d088a983684af"}],"title":"nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89674","datePublished":"2026-09-11T19:45:58.883Z","dateReserved":"2026-09-11T19:38:34.746Z","dateUpdated":"2026-09-11T19:45:58.883Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:54","lastModifiedDate":"2026-09-11 20:19:54","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89674","Ordinal":"1","Title":"nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget","CVE":"CVE-2026-89674","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89674","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget"}]}}}