{"id":"CVE-2026-64031","summary":"erofs: fix managed cache race for unaligned extents","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nerofs: fix managed cache race for unaligned extents\n\nAfter unaligned compressed extents were introduced, the following race\ncould occur:\n\n[Thread 1]                                   [Thread 2]\n(z_erofs_fill_bio_vec)\n\u003chandle a Z_EROFS_PREALLOCATED_FOLIO folio\u003e\n...\nfilemap_add_folio (1)\n                                             (z_erofs_bind_cache)\n                                             \u003cthe same folio is found..\u003e\n                                             ..\n                                             ..\nfolio_attach_private (2)\n                                             filemap_add_folio (3) again\n\nSince (1) is executed but (2) hasn't been executed yet, it's possible\nthat another thread finds the same managed folio in z_erofs_bind_cache()\nfor a different pcluster and calls filemap_add_folio() again since\nfolio-\u003eprivate is still Z_EROFS_PREALLOCATED_FOLIO.\n\nFix this by explicitly clearing folio-\u003eprivate before making the folio\nvisible in the managed cache so that another pcluster can simply wait\non the locked managed folio as what we did for other shared cases [1].\n\nThis only impacts unaligned data compression (`-E48bit` with zstd,\nfor example).\n\n[1] Commit 9e2f9d34dd12 (\"erofs: handle overlapped pclusters out of\n crafted images properly\") was originally introduced to handle crafted\n overlapped extents, but it addresses unaligned extents as well.","modified":"2026-07-22T03:32:04.621901825Z","published":"2026-07-19T15:39:21.609Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64031.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/038166f873c4caf6e85cfd4ea0c5a5ba297b4e8b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/425d32d6288d7d845e486af9419bbedccd8c9103"},{"type":"WEB","url":"https://git.kernel.org/stable/c/649932fc3815eda2f24eb4de4b3a5e94886ee0b9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64031.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64031"},{"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":"7361d1e3763baaf7b9349c576137851458ad38d1"},{"fixed":"425d32d6288d7d845e486af9419bbedccd8c9103"},{"fixed":"038166f873c4caf6e85cfd4ea0c5a5ba297b4e8b"},{"fixed":"649932fc3815eda2f24eb4de4b3a5e94886ee0b9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64031.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.15.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64031.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}