CVE Catalog

CVE-2025-40307

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.14%

4th percentile - higher than 4% of all known CVEs

Summary

In the Linux kernel's exfat filesystem, cluster allocation bits in the bitmap were not validated. An attacker could craft an exfat image with an invalid bitmap, causing overwrite of existing entries during directory creation. The fix adds validation that bitmap clusters are marked as in-use.

Risk Assessment

Potential overwrite of system or user data, leading to filesystem corruption and possible data loss.

Recommendation

Apply the kernel patch that validates the exfat allocation bitmap.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS