CVE-2026-89525

udf: reject VAT indexes equal to the entry count

State: Published
Severity: Not scored
Published: Sep 11, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

udf: reject VAT indexes equal to the entry count

UDF 1.50 virtual partition mapping uses the VAT as an array of physical block mappings. s_num_entries stores the number of entries in that array, not the highest valid index. The valid VAT indexes are therefore below s_num_entries.

udf_get_pblock_virt15() currently rejects only indexes greater than s_num_entries. A crafted image can request index s_num_entries, pass the bounds check, and make the kernel read one entry past the allocated VAT table.

Change the check to reject block >= s_num_entries, so the count is handled as an exclusive upper bound.

A crafted UDF image reproduced this on origin/master commit 0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53 with a KASAN slab-out-of-bounds report in udf_get_pblock_virt15().

Trail of Bits has a reproducer that triggers kernel panic demonstrating the bug, and can share it if needed.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f64e01a90326bb85a3cc8aa0199931dc2f15b589Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 8a8c1c42a34349a0626d910abbad5a29136446b7Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b77b83f5529a26d084d64ece98abd6f0cc86e053Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 9193368408d792cec2057628d87862140fb1ce1cAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b95c33a4e743874f1b0a45bf2aaa4da553552bd1Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 1bd7947f1463c21edafa256d0fbec5b99215e2b6Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before cac0cb07f29ccfb373fd4a36c81e908ef3ce608cAffected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 5.10.270 through 5.10.Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.109 through 6.12.Not affected 6.18.50 through 6.18.Not affected 7.2.4 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f64e01a90326bb85a3cc8aa0199931dc2f15b589Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 8a8c1c42a34349a0626d910abbad5a29136446b7Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b77b83f5529a26d084d64ece98abd6f0cc86e053Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 9193368408d792cec2057628d87862140fb1ce1cAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b95c33a4e743874f1b0a45bf2aaa4da553552bd1Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 1bd7947f1463c21edafa256d0fbec5b99215e2b6Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before cac0cb07f29ccfb373fd4a36c81e908ef3ce608cAffected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
5.10.270 through 5.10.*Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.109 through 6.12.*Not affected
6.18.50 through 6.18.*Not affected
7.2.4 through 7.2.*Not affected
7.3 and laterNot affected

References

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