{"api_version":"1","generated_at":"2026-07-26T14:51:25+00:00","cve":"CVE-2026-64298","urls":{"html":"https://cve.report/CVE-2026-64298","api":"https://cve.report/api/cve/CVE-2026-64298.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64298","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64298"},"summary":{"title":"NFSv4: include MAY_WRITE in open permission mask for O_TRUNC","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: include MAY_WRITE in open permission mask for O_TRUNC\n\nPOSIX requires write permission to truncate a file, so an open() that\nspecifies O_TRUNC must be authorized for write access regardless of the\nO_ACCMODE access mode.\n\nnfs_open_permission_mask() builds the access mask passed to\nnfs_may_open(), which is the local authorization gate for OPENs the\nclient serves itself from a cached write delegation via the\ncan_open_delegated() path in nfs4_try_open_cached().  The mask is\nderived from O_ACCMODE alone, so an open(O_RDONLY | O_TRUNC) against a\nfile the caller cannot write requests only MAY_READ and passes the\nlocal check.  The OPEN is then satisfied locally and the truncation is\nissued to the server as a SETATTR(size=0) over the delegation stateid,\nwhich the server accepts under standard write-delegation semantics.\nPOSIX requires that this open fail with EACCES.\n\nInclude MAY_WRITE in the mask whenever O_TRUNC is set so the local\ncheck matches the access the server would have enforced.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:10","updated_at":"2026-07-25 10:17:10"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/cb148a2762d644bff1894728e8835a9a4b84f9ea","name":"https://git.kernel.org/stable/c/cb148a2762d644bff1894728e8835a9a4b84f9ea","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230","name":"https://git.kernel.org/stable/c/6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a937e92c1d00534b5c2e3e9f4381b7e988180797","name":"https://git.kernel.org/stable/c/a937e92c1d00534b5c2e3e9f4381b7e988180797","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e36501b7d4abdcd6d69a7cb901b2f286b7a3d041","name":"https://git.kernel.org/stable/c/e36501b7d4abdcd6d69a7cb901b2f286b7a3d041","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4817c8974315b666e895b7d1bb83cd3664c323b1","name":"https://git.kernel.org/stable/c/4817c8974315b666e895b7d1bb83cd3664c323b1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/22c1fd1355ad4ca27aa7f0fa02719122dd92d9de","name":"https://git.kernel.org/stable/c/22c1fd1355ad4ca27aa7f0fa02719122dd92d9de","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5140f099ecd8a2f2808b7f7b720ee1bad8468974","name":"https://git.kernel.org/stable/c/5140f099ecd8a2f2808b7f7b720ee1bad8468974","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/30fdf4df6c3c00efec947e4ddf97f0fdd4473628","name":"https://git.kernel.org/stable/c/30fdf4df6c3c00efec947e4ddf97f0fdd4473628","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64298","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64298","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be 4817c8974315b666e895b7d1bb83cd3664c323b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be cb148a2762d644bff1894728e8835a9a4b84f9ea git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be 30fdf4df6c3c00efec947e4ddf97f0fdd4473628 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be 22c1fd1355ad4ca27aa7f0fa02719122dd92d9de git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64298","cve":"CVE-2026-64298","epss":"0.002200000","percentile":"0.125980000","score_date":"2026-07-25","updated_at":"2026-07-26 00:12:33"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/nfs/dir.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4817c8974315b666e895b7d1bb83cd3664c323b1","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"cb148a2762d644bff1894728e8835a9a4b84f9ea","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"30fdf4df6c3c00efec947e4ddf97f0fdd4473628","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"22c1fd1355ad4ca27aa7f0fa02719122dd92d9de","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"a937e92c1d00534b5c2e3e9f4381b7e988180797","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"e36501b7d4abdcd6d69a7cb901b2f286b7a3d041","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"},{"lessThan":"5140f099ecd8a2f2808b7f7b720ee1bad8468974","status":"affected","version":"af22f94ae02ab9dd4fd7fe628c8434a59cc293be","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/nfs/dir.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.24"},{"lessThan":"2.6.24","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.261","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.261","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc3","versionStartIncluding":"2.6.24","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: include MAY_WRITE in open permission mask for O_TRUNC\n\nPOSIX requires write permission to truncate a file, so an open() that\nspecifies O_TRUNC must be authorized for write access regardless of the\nO_ACCMODE access mode.\n\nnfs_open_permission_mask() builds the access mask passed to\nnfs_may_open(), which is the local authorization gate for OPENs the\nclient serves itself from a cached write delegation via the\ncan_open_delegated() path in nfs4_try_open_cached().  The mask is\nderived from O_ACCMODE alone, so an open(O_RDONLY | O_TRUNC) against a\nfile the caller cannot write requests only MAY_READ and passes the\nlocal check.  The OPEN is then satisfied locally and the truncation is\nissued to the server as a SETATTR(size=0) over the delegation stateid,\nwhich the server accepts under standard write-delegation semantics.\nPOSIX requires that this open fail with EACCES.\n\nInclude MAY_WRITE in the mask whenever O_TRUNC is set so the local\ncheck matches the access the server would have enforced."}],"providerMetadata":{"dateUpdated":"2026-07-25T08:49:35.101Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4817c8974315b666e895b7d1bb83cd3664c323b1"},{"url":"https://git.kernel.org/stable/c/cb148a2762d644bff1894728e8835a9a4b84f9ea"},{"url":"https://git.kernel.org/stable/c/30fdf4df6c3c00efec947e4ddf97f0fdd4473628"},{"url":"https://git.kernel.org/stable/c/22c1fd1355ad4ca27aa7f0fa02719122dd92d9de"},{"url":"https://git.kernel.org/stable/c/6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230"},{"url":"https://git.kernel.org/stable/c/a937e92c1d00534b5c2e3e9f4381b7e988180797"},{"url":"https://git.kernel.org/stable/c/e36501b7d4abdcd6d69a7cb901b2f286b7a3d041"},{"url":"https://git.kernel.org/stable/c/5140f099ecd8a2f2808b7f7b720ee1bad8468974"}],"title":"NFSv4: include MAY_WRITE in open permission mask for O_TRUNC","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64298","datePublished":"2026-07-25T08:49:35.101Z","dateReserved":"2026-07-19T15:36:31.778Z","dateUpdated":"2026-07-25T08:49:35.101Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:10","lastModifiedDate":"2026-07-25 10:17:10","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64298","Ordinal":"1","Title":"NFSv4: include MAY_WRITE in open permission mask for O_TRUNC","CVE":"CVE-2026-64298","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64298","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: include MAY_WRITE in open permission mask for O_TRUNC\n\nPOSIX requires write permission to truncate a file, so an open() that\nspecifies O_TRUNC must be authorized for write access regardless of the\nO_ACCMODE access mode.\n\nnfs_open_permission_mask() builds the access mask passed to\nnfs_may_open(), which is the local authorization gate for OPENs the\nclient serves itself from a cached write delegation via the\ncan_open_delegated() path in nfs4_try_open_cached().  The mask is\nderived from O_ACCMODE alone, so an open(O_RDONLY | O_TRUNC) against a\nfile the caller cannot write requests only MAY_READ and passes the\nlocal check.  The OPEN is then satisfied locally and the truncation is\nissued to the server as a SETATTR(size=0) over the delegation stateid,\nwhich the server accepts under standard write-delegation semantics.\nPOSIX requires that this open fail with EACCES.\n\nInclude MAY_WRITE in the mask whenever O_TRUNC is set so the local\ncheck matches the access the server would have enforced.","Type":"Description","Title":"NFSv4: include MAY_WRITE in open permission mask for O_TRUNC"}]}}}