{"cve":"CVE-2026-45892","nvd":{"published":"2026-05-27T14:17:03.353","modified":"2026-06-25T21:11:06.653","status":"Analyzed","description":"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          |<-  ->| ----> 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/28db4bfc6f82fd20e2aadb7fc162244109a4eb31","https://git.kernel.org/stable/c/6d882ea3b0931b43530d44149b79fcd4ffc13030","https://git.kernel.org/stable/c/a1b962a821e7a52d48212ae269b45808b4411267","https://git.kernel.org/stable/c/c2ee51d684adca7645e4aa74adca13f6750390bc","https://git.kernel.org/stable/c/d8ee559fccdef713f058cfe5f2c03dc9b18be3b1"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-45892","score":0.0016,"percentile":0.0521,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}