# CVE-2026-89525

## Summary

- **CVE ID:** CVE-2026-89525
- **Severity:** UNKNOWN
- **CVSS Score:** 0
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 16, 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.

## Affected Products

- Linux — Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
- Linux — Linux (2.6.12)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/9193368408d792cec2057628d87862140fb1ce1c)
- [CNA](https://git.kernel.org/stable/c/b95c33a4e743874f1b0a45bf2aaa4da553552bd1)
- [CNA](https://git.kernel.org/stable/c/1bd7947f1463c21edafa256d0fbec5b99215e2b6)
- [CNA](https://git.kernel.org/stable/c/cac0cb07f29ccfb373fd4a36c81e908ef3ce608c)
- [CNA](https://git.kernel.org/stable/c/f64e01a90326bb85a3cc8aa0199931dc2f15b589)
- [CNA](https://git.kernel.org/stable/c/8a8c1c42a34349a0626d910abbad5a29136446b7)
- [CNA](https://git.kernel.org/stable/c/19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4)
- [CNA](https://git.kernel.org/stable/c/b77b83f5529a26d084d64ece98abd6f0cc86e053)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 8.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._