Use-after-free in Linux kernel - CVE-2026-68148

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Main Vulnerability Database Vulnerabilities #VU142166

Use-after-free in Linux kernel - CVE-2026-68148

Published: August 12, 2026


Vulnerability identifier: #VU142166
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-68148
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a use-after-free.

The vulnerability exists due to a use-after-free in find_or_insert_direct_key() when reusing cached direct keys for inodes from different super_blocks. A local user can cause different super_blocks to reference the same cached direct key to cause a use-after-free.

The issue affects the legacy fscrypt_direct_keys table used by v1 encryption policies with FSCRYPT_POLICY_FLAG_DIRECT_KEY, while the v2 policy equivalent is not affected.


Affected software

Linux kernel
Ubuntu
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

How to mitigate CVE-2026-68148

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-gcp-7.0 (Ubuntu package) - addressed in versions 7.0.0-38.38~24.04.4, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14~24.04.1
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1

External References

Related Security Bulletins