{"id":"CVE-2026-45892","summary":"ext4: drop extent cache after doing PARTIAL_VALID1 zeroout","details":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: drop extent cache after doing PARTIAL_VALID1 zeroout\n\nWhen splitting an unwritten extent in the middle and converting it to\ninitialized in ext4_split_extent() with the EXT4_EXT_MAY_ZEROOUT and\nEXT4_EXT_DATA_VALID2 flags set, it could leave a stale unwritten extent.\n\nAssume we have an unwritten file and buffered write in the middle of it\nwithout dioread_nolock enabled, it will allocate blocks as written\nextent.\n\n       0  A      B  N\n       [UUUUUUUUUUUU] on-disk extent      U: unwritten extent\n       [UUUUUUUUUUUU] extent status tree\n       [--DDDDDDDD--]                     D: valid data\n          |\u003c-  -\u003e| ----\u003e this range needs to be initialized\n\next4_split_extent() first try to split this extent at B with\nEXT4_EXT_DATA_PARTIAL_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 leave the entire extent as unwritten.\n\n       0  A      B  N\n       [UUUUUUUUUUUU] on-disk extent\n       [UUUUUUUUUUUU] extent status tree\n       [--DDDDDDDDZZ]                     Z: zeroed 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\nleave an written extent from A to N.\n\n       0  A      B  N\n       [UUWWWWWWWWWW] on-disk extent      W: written extent\n       [UUUUUUUUUUUU] extent status tree\n       [--DDDDDDDDZZ]\n\nFinally ext4_map_create_blocks() only insert extent A to B to the extent\nstatus tree, and leave an stale unwritten extent in the status tree.\n\n       0  A      B  N\n       [UUWWWWWWWWWW] on-disk extent      W: written extent\n       [UUWWWWWWWWUU] extent status tree\n       [--DDDDDDDDZZ]\n\nFix this issue by always cached extent status entry after zeroing out\nthe second part.","modified":"2026-07-11T03:54:26.016614735Z","published":"2026-05-27T12:17:03.175Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45892.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/28db4bfc6f82fd20e2aadb7fc162244109a4eb31"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d882ea3b0931b43530d44149b79fcd4ffc13030"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a1b962a821e7a52d48212ae269b45808b4411267"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c2ee51d684adca7645e4aa74adca13f6750390bc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d8ee559fccdef713f058cfe5f2c03dc9b18be3b1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f0931a5c17005a0c4fc35bd1a001245effc3354b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45892.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45892"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ddf854e59166533b0f46ba32cd6cd9aca3197d1b"},{"fixed":"28db4bfc6f82fd20e2aadb7fc162244109a4eb31"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"58ddae5d77b1db3a27b891c75a8fa120239ac092"},{"fixed":"f0931a5c17005a0c4fc35bd1a001245effc3354b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d17857b4fb9ba5745b59be0ef38fd532991fccbf"},{"fixed":"d8ee559fccdef713f058cfe5f2c03dc9b18be3b1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88"},{"fixed":"c2ee51d684adca7645e4aa74adca13f6750390bc"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"7015fcf473796e1d2d876f241bd9e0c36f3d4eef"},{"fixed":"a1b962a821e7a52d48212ae269b45808b4411267"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1bf6974822d1dba86cf11b5f05498581cf3488a2"},{"fixed":"6d882ea3b0931b43530d44149b79fcd4ffc13030"}]}],"versions":["v6.1.167"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-45892.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.167"},{"fixed":"6.1.168"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-45892.json"}}],"schema_version":"1.7.5"}