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 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 v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

No history.

Information

Published : 2025-12-08 01:16

Updated : 2026-08-19 17:18

NVD link : CVE-2025-40307

Mitre link : CVE-2025-40307

CVE.ORG link : CVE-2025-40307

JSON object : View

Products Affected

No product.

CWE

No CWE.

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