CVE-2026-64323

Technical Description

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

udf: validate VAT header length against the VAT inode size

udf_load_vat() takes the virtual partition's start offset straight from

the on-disk VAT 2.0 header without checking it against the VAT inode

size:

map->s_type_specific.s_virtual.s_start_offset =

le16_to_cpu(vat20->lengthHeader);

map->s_type_specific.s_virtual.s_num_entries =

(sbi->s_vat_inode->i_size -

map->s_type_specific.s_virtual.s_start_offset) >> 2;

lengthHeader is a fully attacker-controlled 16-bit value. If it exceeds

the VAT inode size, the s_num_entries subtraction underflows to a huge

count, which defeats the "block > s_num_entries" bound in

udf_get_pblock_virt15(); and on the ICB-inline path that function reads

((__le32 *)(iinfo->i_data + s_start_offset))[block]

so a large s_start_offset indexes past the inode's in-ICB data. Mounting

a crafted UDF image with a virtual (VAT) partition then triggers an

out-of-bounds read.

Reject a VA

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