CVE-2025-40307exfat: validate cluster allocation bits of the allocation bitmap
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Deferred
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 before 87f827d53bd0688597bda63ae95908e2ad39bac0; from 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 before 67ce8034dc0278ddd88cad93d4218a945180dddd; from 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 before 6bc58b4c53795ab5fe00648344aa7d9d61175f90; from 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 before 13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf; from 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 before 79c1587b6cda74deb0c86fc7ba194b92958c793c | CNA record |
References
- https://git.kernel.org/stable/c/87f827d53bd0688597bda63ae95908e2ad39bac0
- https://git.kernel.org/stable/c/67ce8034dc0278ddd88cad93d4218a945180dddd
- https://git.kernel.org/stable/c/6bc58b4c53795ab5fe00648344aa7d9d61175f90
- https://git.kernel.org/stable/c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf
- https://git.kernel.org/stable/c/79c1587b6cda74deb0c86fc7ba194b92958c793c
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.