# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-97224, BELL-CVE-2026-74595, DEBIAN-CVE-2026-74595, GHSA-7jrv-8xmf-x8j2, UBUNTU-CVE-2026-74595

## 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.

## Is CVE-2026-74595 being exploited?

There is no known exploitation of CVE-2026-74595 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74595 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-74595 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74595/ (Markdown: https://insights.sbomify.com/CVE-2026-74595/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74595
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74595
- OSV: https://osv.dev/vulnerability/CVE-2026-74595

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74595/
Summaries are generated and may contain mistakes; the official description above is the record.