{"id":"CVE-2026-45858","state":"PUBLISHED","title":"ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1\n\nWhen allocating initialized blocks from a large unwritten extent, or\nwhen splitting an unwritten extent during end I/O and converting it to\ninitialized, there is currently a potential issue of stale data if the\nextent needs to be split in the middle.\n\n       0  A      B  N\n       [UUUUUUUUUUUU]    U: unwritten extent\n       [--DDDDDDDD--]    D: valid data\n          |<-  ->| ----> this range needs to be initialized\n\next4_split_extent() first try to split this extent at B with\nEXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but\next4_split_extent_at() failed to split this extent due to temporary lack\nof space. It zeroout B to N and mark the entire extent from 0 to N\nas written.\n\n       0  A      B  N\n       [WWWWWWWWWWWW]    W: written extent\n       [SSDDDDDDDDZZ]    Z: zeroed, S: stale data\n\next4_split_extent() then try to split this extent at A with\nEXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left\na stale written extent from 0 to A.\n\n       0  A      B   N\n       [WW|WWWWWWWWWW]\n       [SS|DDDDDDDDZZ]\n\nFix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at()\nwhen splitting at B, don't convert the entire extent to written and left\nit as unwritten after zeroing out B to N. The remaining work is just\nlike the standard two-part split. ext4_split_extent() will pass the\nEXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the\nsecond time, allowing it to properly handle the split. If the split is\nsuccessful, it will keep extent from 0 to A as unwritten.","publishedAt":"2026-05-27T12:15:37.738Z","updatedAt":"2026-05-30T10:41:40.719Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"58ddae5d77b1db3a27b891c75a8fa120239ac092","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"d17857b4fb9ba5745b59be0ef38fd532991fccbf","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"7015fcf473796e1d2d876f241bd9e0c36f3d4eef","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"1bf6974822d1dba86cf11b5f05498581cf3488a2","versionType":"git"},{"version":"814a7833df19e1de7447f870ae890adb12561627","status":"affected","versionType":"git"},{"version":"4319fd00002630a761fa5559a086f11ed7623006","status":"affected","versionType":"git"},{"version":"e28b27be06c5e6a5236c0c0b370ca0768ab086bb","status":"affected","versionType":"git"},{"version":"3.2.33","status":"affected","lessThan":"3.3","versionType":"semver"},{"version":"3.4.16","status":"affected","lessThan":"3.5","versionType":"semver"},{"version":"3.6.4","status":"affected","lessThan":"3.7","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/extents.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.7","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/extents.c"]}],"references":["https://git.kernel.org/stable/c/58ddae5d77b1db3a27b891c75a8fa120239ac092","https://git.kernel.org/stable/c/d17857b4fb9ba5745b59be0ef38fd532991fccbf","https://git.kernel.org/stable/c/d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88","https://git.kernel.org/stable/c/7015fcf473796e1d2d876f241bd9e0c36f3d4eef","https://git.kernel.org/stable/c/1bf6974822d1dba86cf11b5f05498581cf3488a2"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45858.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45858","state":"PUBLISHED","datePublished":"2026-05-27T12:15:37.738Z","dateUpdated":"2026-05-30T10:41:40.719Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.079Z"},"containers":{"cna":{"title":"ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1\n\nWhen allocating initialized blocks from a large unwritten extent, or\nwhen splitting an unwritten extent during end I/O and converting it to\ninitialized, there is currently a potential issue of stale data if the\nextent needs to be split in the middle.\n\n       0  A      B  N\n       [UUUUUUUUUUUU]    U: unwritten extent\n       [--DDDDDDDD--]    D: valid data\n          |<-  ->| ----> this range needs to be initialized\n\next4_split_extent() first try to split this extent at B with\nEXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but\next4_split_extent_at() failed to split this extent due to temporary lack\nof space. It zeroout B to N and mark the entire extent from 0 to N\nas written.\n\n       0  A      B  N\n       [WWWWWWWWWWWW]    W: written extent\n       [SSDDDDDDDDZZ]    Z: zeroed, S: stale data\n\next4_split_extent() then try to split this extent at A with\nEXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left\na stale written extent from 0 to A.\n\n       0  A      B   N\n       [WW|WWWWWWWWWW]\n       [SS|DDDDDDDDZZ]\n\nFix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at()\nwhen splitting at B, don't convert the entire extent to written and left\nit as unwritten after zeroing out B to N. The remaining work is just\nlike the standard two-part split. ext4_split_extent() will pass the\nEXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the\nsecond time, allowing it to properly handle the split. If the split is\nsuccessful, it will keep extent from 0 to A as unwritten."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"58ddae5d77b1db3a27b891c75a8fa120239ac092","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"d17857b4fb9ba5745b59be0ef38fd532991fccbf","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"7015fcf473796e1d2d876f241bd9e0c36f3d4eef","versionType":"git"},{"version":"dee1f973ca341c266229faa5a1a5bb268bed3531","status":"affected","lessThan":"1bf6974822d1dba86cf11b5f05498581cf3488a2","versionType":"git"},{"version":"814a7833df19e1de7447f870ae890adb12561627","status":"affected","versionType":"git"},{"version":"4319fd00002630a761fa5559a086f11ed7623006","status":"affected","versionType":"git"},{"version":"e28b27be06c5e6a5236c0c0b370ca0768ab086bb","status":"affected","versionType":"git"},{"version":"3.2.33","status":"affected","lessThan":"3.3","versionType":"semver"},{"version":"3.4.16","status":"affected","lessThan":"3.5","versionType":"semver"},{"version":"3.6.4","status":"affected","lessThan":"3.7","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/extents.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.7","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/extents.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/58ddae5d77b1db3a27b891c75a8fa120239ac092"},{"url":"https://git.kernel.org/stable/c/d17857b4fb9ba5745b59be0ef38fd532991fccbf"},{"url":"https://git.kernel.org/stable/c/d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88"},{"url":"https://git.kernel.org/stable/c/7015fcf473796e1d2d876f241bd9e0c36f3d4eef"},{"url":"https://git.kernel.org/stable/c/1bf6974822d1dba86cf11b5f05498581cf3488a2"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-30T10:41:40.719Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.7","versionEndExcluding":"6.6.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.7","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.7","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.7","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.7","versionEndExcluding":"7.0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.2.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6.4"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}