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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.

PUBLISHED Reserved 2025-04-16 | Published 2025-12-08 | Updated 2025-12-08 | Assigner Linux

Product status

Default status
unaffected

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 6bc58b4c53795ab5fe00648344aa7d9d61175f90
affected

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf
affected

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 79c1587b6cda74deb0c86fc7ba194b92958c793c
affected

Default status
affected

6.12.58 (semver)
unaffected

6.17.8 (semver)
unaffected

6.18 (original_commit_for_fix)
unaffected

References

git.kernel.org/...c/6bc58b4c53795ab5fe00648344aa7d9d61175f90

git.kernel.org/...c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf

git.kernel.org/...c/79c1587b6cda74deb0c86fc7ba194b92958c793c

cve.org (CVE-2025-40307)

nvd.nist.gov (CVE-2025-40307)

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