Improper access control in Linux kernel - CVE-2026-74595
Published: August 24, 2026
Vulnerability identifier: #VU144974
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-74595
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to bypass owner checks and set an encryption policy on a file.
The vulnerability exists due to improper access control in fscrypt_ioctl_set_policy() when handling ioctl requests on idmapped mounts. A local user can issue a crafted ioctl on an idmapped mount to bypass owner checks and set an encryption policy on a file.
The issue occurs because the check uses the unmapped on-disk owner rather than the mapped owner on mounts that support idmapping.
Affected software
Linux kernel
Debian Linux
linux (Debian package)
Debian Linux
linux (Debian package)
How to mitigate CVE-2026-74595
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.105-1
linux (Debian package) - update to 6.12.105-1
External References
- https://git.kernel.org/stable/c/0baeb730044981f5ec5fb7d62a3763835ea606f6
- https://git.kernel.org/stable/c/174633a468817a49bd474bcfc9067c84e54efe68
- https://git.kernel.org/stable/c/33b7e810ce09955aa02f3b632455cf5e7ac990a9
- https://git.kernel.org/stable/c/653e888a24c87b8bbeab44d7e558a1c1a3641088
- https://git.kernel.org/stable/c/6a67c460b12315033268dce597546984fe5739e7
- https://git.kernel.org/stable/c/98516ba8b817f34e86bdd7a5b7a383cff75c3ddf
- https://git.kernel.org/stable/c/cf6c993c0feca7984797e634deba3c80342e199a