CVE-2025-40307
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.15% probability · 4th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.