Description
In the Linux kernel, the following vulnerability has been resolved:
exfat: validate cluster allocation bits of the allocation bitmap
syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HAffected software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003, < 87f827d53bd0688597bda63ae95908e2ad39bac0; >= 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003, < 67ce8034dc0278ddd88cad93d4218a945180dddd; >= 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003, < 6bc58b4c53795ab5fe00648344aa7d9d61175f90; >= 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003, < 13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf; >= 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003, < 79c1587b6cda74deb0c86fc7ba194b92958c793c |
| Linux | Linux | 5.7 |
References
- https://git.kernel.org/stable/c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf
- https://git.kernel.org/stable/c/67ce8034dc0278ddd88cad93d4218a945180dddd
- https://git.kernel.org/stable/c/6bc58b4c53795ab5fe00648344aa7d9d61175f90
- https://git.kernel.org/stable/c/79c1587b6cda74deb0c86fc7ba194b92958c793c
- https://git.kernel.org/stable/c/87f827d53bd0688597bda63ae95908e2ad39bac0
Timeline
- Published
- Dec 8, 2025
- Last modified
- Oct 15, 2026
- NVD status
- Deferred