# CVE-2026-78410: Util-linux: util-linux: restricted bind mounts do not pin the source, allowing x-mount.owner/group/mode redirection

> Local attackers can exploit a race condition in restricted bind mounts to redirect SUID mount operations, potentially modifying file ownership or permissions.

- **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:** 2 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** ALPINE-CVE-2026-78410, AZL-99390, BELL-CVE-2026-78410, CVE-2026-104886, DEBIAN-CVE-2026-78410, ECHO-5339-ad7c-f545, ROOT-OS-DEBIAN-12-CVE-2026-78410, ROOT-OS-DEBIAN-13-CVE-2026-78410, UBUNTU-CVE-2026-78410

## What is CVE-2026-78410?

CVE-2026-78410 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 2 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount(8) to bind another host directory. If the fstab entry also sets X-mount.owner, X-mount.group, or X-mount.mode, root then changes ownership or mode on that redirected inode.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-78410?


## How do I fix CVE-2026-78410?

Apply the vendor's patch.

## Is CVE-2026-78410 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-78410 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78410 and fix it if it is affected.

What it is: CVE-2026-78410 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 2 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-78410 exists.

Affected product: Red Hat Enterprise Linux 10. 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-2026-78410/ (Markdown: https://insights.sbomify.com/CVE-2026-78410/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78410
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78410
- OSV: https://osv.dev/vulnerability/CVE-2026-78410

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78410/
Summaries are generated and may contain mistakes; the official description above is the record.