CVE-2026-64323 - Vulnerability Details

- udf: validate VAT header length against the VAT inode size

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.

Published: 2026-07-25

Score: n/a

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< 0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< 883962731420ec271ed8c1cd76524f4b17faa982
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< 2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< 55287a3555ff0515b3aff181d2c08c0462a41709
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< 74580fdf022909e184223cacc364feb826982d96
`fa5e08156335d0687c85b4e724db9448fb166601`	affected	< d8202786b3d75125c84ebc4de6d946f92fde0ee8

Linux

affected

Version	Status	Constraints
`2.6.26`	affected	—
`0`	unaffected	< 2.6.26
`5.10.261`	unaffected	≤ 5.10.*
`5.15.212`	unaffected	≤ 5.15.*
`6.1.178`	unaffected	≤ 6.1.*
`6.6.145`	unaffected	≤ 6.6.*
`6.12.96`	unaffected	≤ 6.12.*
`6.18.39`	unaffected	≤ 6.18.*
`7.1.4`	unaffected	≤ 7.1.*
`7.2-rc1`	unaffected	≤ *

No data.

No data available yet.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934
https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63
https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709
https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96
https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982
https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb
https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8
https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad

History

Sat, 25 Jul 2026 09:30:00 +0000

Type	Values Removed	Values Added
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.
Title		udf: validate VAT header length against the VAT inode size
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934 https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63 https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709 https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96 https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982 https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8 https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-07-25T08:49:51.097Z

Updated: 2026-07-25T08:49:51.097Z

Reserved: 2026-07-19T15:36:31.780Z

Link: CVE-2026-64323

Vulnrichment

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NVD

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Redhat

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OpenCVE Enrichment

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Weaknesses

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Tracking

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