udf: validate VAT header length against the VAT inode size

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64323
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:13 UTC
Updated2026-07-27 05:16:42 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS: 0.001600000 probability, percentile 0.055770000 (date 2026-07-29)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934 git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 883962731420ec271ed8c1cd76524f4b17faa982 git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63 git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 55287a3555ff0515b3aff181d2c08c0462a41709 git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 74580fdf022909e184223cacc364feb826982d96 git Not specified
CNA Linux Linux affected fa5e08156335d0687c85b4e724db9448fb166601 d8202786b3d75125c84ebc4de6d946f92fde0ee8 git Not specified
CNA Linux Linux affected 2.6.26 Not specified
CNA Linux Linux unaffected 2.6.26 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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