CVE-2026-45991

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References