CVE-2026-64323
Received
Received - Intake
UDF Filesystem Out-of-Bounds Read via VAT Header
Vulnerability report for CVE-2026-64323, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-25
Last updated on: 2026-07-25
Assigner: kernel.org
Description
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 VAT whose header length does not leave room for at least one
entry within the VAT inode.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
