{"id":"CVE-2026-90260","summary":"btrfs: zoned: don't clobber the extent buffer when zeroing it out","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zoned: don't clobber the extent buffer when zeroing it out\n\nOn a zoned filesystem a freed-but-still-dirty tree block is written out\nas zeros (EXTENT_BUFFER_ZONED_ZEROOUT) only to keep the zone write\npointer advancing. btree_csum_one_bio() implemented this by memzeroing\nthe extent buffer's own folios before submission.\n\nThat destroys the in-memory buffer while it may still be referenced. In\nparticular btrfs_free_tree_block() can run on it afterwards and reads\nthe header to add a delayed reference; once the header has been zeroed\nit frees bytenr 0 and corrupts the extent tree (the\nbtrfs_header_bytenr(buf) != 0 ASSERT in btrfs_free_tree_block(), or an\n\"unable to find ref\" abort). It is flaky and reproduces under fsstress,\ne.g. generic/461 and generic/013.\n\nWrite the zeros to disk from the shared zero page instead and leave the\nextent buffer content untouched, so any later reference - including the\ndelayed reference from btrfs_free_tree_block() - still sees a valid\nheader. end_bbio_meta_write() now clears writeback on the buffer's own\nfolios, as the bio no longer carries them.","modified":"2026-09-19T03:47:25.499023233Z","published":"2026-09-17T16:07:58.102Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90260.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/92484ad014f2e2b0e0e7bbc1610951e978cf557c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/98e3747587f9f87f010d8d7e55786216249a94af"},{"type":"WEB","url":"https://git.kernel.org/stable/c/db4b9eefc8ee0bcaeee4d5e6a7313905f6a2fe7c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90260.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90260"},{"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":"aa6313e6ff2bfbf736a2739047bba355d8241584"},{"fixed":"92484ad014f2e2b0e0e7bbc1610951e978cf557c"},{"fixed":"98e3747587f9f87f010d8d7e55786216249a94af"},{"fixed":"db4b9eefc8ee0bcaeee4d5e6a7313905f6a2fe7c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90260.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.8.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90260.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"}]}