---
id: CVE-2026-89525
title: 'udf: reject VAT indexes equal to the entry count'
summary: |-
  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 numbe…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-1285
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    f64e01a90326bb85a3cc8aa0199931dc2f15b589
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    8a8c1c42a34349a0626d910abbad5a29136446b7
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    b77b83f5529a26d084d64ece98abd6f0cc86e053
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    9193368408d792cec2057628d87862140fb1ce1c
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    b95c33a4e743874f1b0a45bf2aaa4da553552bd1
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    1bd7947f1463c21edafa256d0fbec5b99215e2b6
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    cac0cb07f29ccfb373fd4a36c81e908ef3ce608c
  - Linux 2.6.12
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:48:16.507Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89525'
references:
  - url: 'https://git.kernel.org/stable/c/f64e01a90326bb85a3cc8aa0199931dc2f15b589'
  - url: 'https://git.kernel.org/stable/c/8a8c1c42a34349a0626d910abbad5a29136446b7'
  - url: 'https://git.kernel.org/stable/c/19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4'
  - url: 'https://git.kernel.org/stable/c/b77b83f5529a26d084d64ece98abd6f0cc86e053'
  - url: 'https://git.kernel.org/stable/c/9193368408d792cec2057628d87862140fb1ce1c'
  - url: 'https://git.kernel.org/stable/c/b95c33a4e743874f1b0a45bf2aaa4da553552bd1'
  - url: 'https://git.kernel.org/stable/c/1bd7947f1463c21edafa256d0fbec5b99215e2b6'
  - url: 'https://git.kernel.org/stable/c/cac0cb07f29ccfb373fd4a36c81e908ef3ce608c'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89525.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89525'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532509'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89525'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89525'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89525.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00184
epssPercentile: 0.07964
ingestedAt: '2026-09-14T15:23:07.452Z'
---

## Overview

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

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f64e01a90326bb85a3cc8aa0199931dc2f15b589`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8a8c1c42a34349a0626d910abbad5a29136446b7`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b77b83f5529a26d084d64ece98abd6f0cc86e053`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9193368408d792cec2057628d87862140fb1ce1c`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b95c33a4e743874f1b0a45bf2aaa4da553552bd1`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1bd7947f1463c21edafa256d0fbec5b99215e2b6`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < cac0cb07f29ccfb373fd4a36c81e908ef3ce608c`
- `Linux 2.6.12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89525.json)