PT-2026-43858 · Linux · Linux

Published 2026-05-27 · Updated 2026-05-27 · CVE-2026-45991

Mitre

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

udf: fix partition descriptor append bookkeeping

Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in part descs loc[].

handle partition descriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and num part descs keeps growing.

Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by num part descs. If partnum is already aligned to PART DESC ALLOC STEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table.

Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model.

Fix

Related Identifiers

CVE-2026-45991

Affected Products

Linux

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-45991 · Security Note
• https://git.kernel.org/stable/c/b5597bb83fc37b5b5da74a4453fa920b932cf39a · Note
• https://git.kernel.org/stable/c/08fa5d818e5bf53c7ca234d88ba334f32004e9b6 · Note
• https://git.kernel.org/stable/c/08841b06fa64d8edbd1a21ca6e613420c90cc4b8 · Note
• https://git.kernel.org/stable/c/058b451b1039f056d1362c4fec2229e522366ab0 · Note