Vulnerability 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 Score
HIGH
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
FAQ
What is CVE-2025-40307?
CVE-2025-40307 is a vulnerability with a CVSS score of 7.8 (HIGH). 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 a...
How severe is CVE-2025-40307?
CVE-2025-40307 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-40307?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.