Main Vulnerability Database Vulnerabilities #VU139680

Improper access control in Linux kernel - CVE-2026-64294

Published: July 27, 2026

Vulnerability identifier: #VU139680

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64294

CWE-ID: CWE-284

Exploitation vector: Local access

Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to improper access control in the mincore() and madvise(MADV_PAGEOUT) ownership checks when handling files on idmapped mounts. A local user can access these interfaces on a crafted idmapped mount to disclose sensitive information.

The issue affects side-channel protection logic and occurs because ownership was checked against an idmap that ignored the file's mount idmap.

Affected software

Linux kernel

How to mitigate CVE-2026-64294

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3

External References

Related Security Bulletins