CVE-2026-89525
udf: reject VAT indexes equal to the entry count
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.
INFO
Published Date :
Sept. 11, 2026, 8:19 p.m.
Last Modified :
Sept. 14, 2026, 1:19 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest stable version.
- Apply the provided patch for the UDF module.
- Recompile the kernel if you are using custom modules.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-89525.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89525 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89525
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-89525 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89525 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 14, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89525.json">CVE-2026-89525</a> Added Reference https://git.kernel.org/stable/c/19f36c6453cd88fe6d60ef36ab1f1cad8ddf4ce4 Added Reference https://git.kernel.org/stable/c/8a8c1c42a34349a0626d910abbad5a29136446b7 Added Reference https://git.kernel.org/stable/c/b77b83f5529a26d084d64ece98abd6f0cc86e053 Added Reference https://git.kernel.org/stable/c/f64e01a90326bb85a3cc8aa0199931dc2f15b589 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 11, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89525.json">CVE-2026-89525</a> Added Reference https://git.kernel.org/stable/c/1bd7947f1463c21edafa256d0fbec5b99215e2b6 Added Reference https://git.kernel.org/stable/c/9193368408d792cec2057628d87862140fb1ce1c Added Reference https://git.kernel.org/stable/c/b95c33a4e743874f1b0a45bf2aaa4da553552bd1 Added Reference https://git.kernel.org/stable/c/cac0cb07f29ccfb373fd4a36c81e908ef3ce608c