CVE-2026-74595 fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()
An attacker on an idmapped mount can bypass owner checks to set encryption policies, potentially gaining unauthorized access or privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74595?
CVE-2026-74595 is a high-severity authentication bypass vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()
fscrypt_ioctl_set_policy() calls inode_owner_or_capable() with &nop_mnt_idmap before allowing an encryption policy to be set, instead of the idmap of the mount the ioctl was issued on.
fscrypt is used by filesystems that support idmapped mounts (e.g. ext4, f2fs), so on such a mount this compares the caller's fsuid against the unmapped on-disk owner rather than the mapped owner: the actual owner can be wrongly denied with -EACCES and an unrelated caller wrongly allowed. Use file_mnt_idmap(filp) instead.
Which versions are affected by CVE-2026-74595?
How do I fix CVE-2026-74595?
Apply the vendor's patch.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-74595 being exploited?
There is no known exploitation of CVE-2026-74595 in the wild and no public exploit code.
Sources
Also known as AZL-97224, BELL-CVE-2026-74595, DEBIAN-CVE-2026-74595, GHSA-7jrv-8xmf-x8j2, UBUNTU-CVE-2026-74595.