CVE-2026-64323

Kernel-memory disclosure and crash via unchecked VAT length

Published Jul 25, 2026 · Updated Jul 25, 2026

Out-of-bounds read in the Linux Kernel UDF filesystem allows local users to disclose kernel memory or crash the host via a crafted image. udf_load_vat() trusts the attacker-controlled VAT 2.0 lengthHeader value as s_start_offset; when it exceeds the VAT inode size, entry-count subtraction underflows and udf_get_pblock_virt15() indexes beyond inline inode data. Exploitation requires mounting a crafted UDF image with a virtual partition; direct mounting needs CAP_SYS_ADMIN, while common UDisks/polkit deployments can expose the path to low-privileged local users.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux Kernel UDF filesystem allows local users to disclose kernel memory or crash the host via a crafted image. udf_load_vat() trusts the attacker-controlled VAT 2.0 lengthHeader value as s_start_offset; when it exceeds the VAT inode size, entry-count subtraction underflows and udf_get_pblock_virt15() indexes beyond inline inode data. Exploitation requires mounting a crafted UDF image with a virtual partition; direct mounting needs CAP_SYS_ADMIN, while common UDisks/polkit deployments can expose the path to low-privileged local users.

The record

CVE
CVE-2026-64323
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.26
  2. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934
  3. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63
  4. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <55287a3555ff0515b3aff181d2c08c0462a41709
  5. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <74580fdf022909e184223cacc364feb826982d96
  6. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <883962731420ec271ed8c1cd76524f4b17faa982
  7. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb
  8. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <d8202786b3d75125c84ebc4de6d946f92fde0ee8
  9. Affected versionversion=fa5e08156335d0687c85b4e724db9448fb166601 <e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.26; version=fa5e08156335d0687c85b4e724db9448fb166601 <0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934; version=fa5e08156335d0687c85b4e724db9448fb166601 <2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63; version=fa5e08156335d0687c85b4e724db9448fb166601 <55287a3555ff0515b3aff181d2c08c0462a41709; version=fa5e08156335d0687c85b4e724db9448fb166601 <74580fdf022909e184223cacc364feb826982d96; version=fa5e08156335d0687c85b4e724db9448fb166601 <883962731420ec271ed8c1cd76524f4b17faa982; version=fa5e08156335d0687c85b4e724db9448fb166601 <bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb; version=fa5e08156335d0687c85b4e724db9448fb166601 <d8202786b3d75125c84ebc4de6d946f92fde0ee8; version=fa5e08156335d0687c85b4e724db9448fb166601 <e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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