{"id":"CVE-2025-40307","summary":"exfat: validate cluster allocation bits of the allocation bitmap","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nexfat: validate cluster allocation bits of the allocation bitmap\n\nsyzbot created an exfat image with cluster bits not set for the allocation\nbitmap. exfat-fs reads and uses the allocation bitmap without checking\nthis. The problem is that if the start cluster of the allocation bitmap\nis 6, cluster 6 can be allocated when creating a directory with mkdir.\nexfat zeros out this cluster in exfat_mkdir, which can delete existing\nentries. This can reallocate the allocated entries. In addition,\nthe allocation bitmap is also zeroed out, so cluster 6 can be reallocated.\nThis patch adds exfat_test_bitmap_range to validate that clusters used for\nthe allocation bitmap are correctly marked as in-use.","modified":"2026-04-02T12:48:21.733522Z","published":"2025-12-08T00:46:32.659Z","related":["SUSE-SU-2026:0278-1","SUSE-SU-2026:0281-1","SUSE-SU-2026:0315-1","SUSE-SU-2026:20207-1","SUSE-SU-2026:20220-1","SUSE-SU-2026:20228-1","SUSE-SU-2026:20477-1","SUSE-SU-2026:20498-1","SUSE-SU-2026:20845-1","SUSE-SU-2026:20876-1","openSUSE-SU-2026:20145-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40307.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6bc58b4c53795ab5fe00648344aa7d9d61175f90"},{"type":"WEB","url":"https://git.kernel.org/stable/c/79c1587b6cda74deb0c86fc7ba194b92958c793c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40307.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40307"},{"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":"1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003"},{"fixed":"6bc58b4c53795ab5fe00648344aa7d9d61175f90"},{"fixed":"13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf"},{"fixed":"79c1587b6cda74deb0c86fc7ba194b92958c793c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40307.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.7.0"},{"fixed":"6.12.58"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40307.json"}}],"schema_version":"1.7.5"}