# CVE-2026-101304: Multiple jail filesystem root escapes

> A process in a FreeBSD jail can escape filesystem root restrictions if fdescfs is mounted with the nodup option, allowing unauthorized access to host files.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **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:** No
- **Published:** 15 Oct 2026
- **Updated:** 20 Oct 2026

## What is CVE-2026-101304?

CVE-2026-101304 is a high-severity vulnerability in Freebsd Freebsd, published on 15 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

When fdescfs(4) was mounted in a jail with the "nodup" option, opening /dev/fd/N returned a descriptor that did not inherit FD_RESOLVE_BENEATH or the Capsicum capability rights of descriptor N.

A process in a jail that has received a directory file descriptor from another jail can use these techniques to escape the jail's filesystem root restriction.

Weakness: CWE-273 (Improper Check for Dropped Privileges)

## Which versions are affected by CVE-2026-101304?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-101304?

No fix has been published for CVE-2026-101304 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101304 being exploited?

There is no known exploitation of CVE-2026-101304 in the wild and no public exploit code.

## Other vulnerabilities in Freebsd Freebsd

- [CVE-2018-17160](https://insights.sbomify.com/CVE-2018-17160/): Memory corruption in FreeBSD (critical 10.0)
- [CVE-2014-3954](https://insights.sbomify.com/CVE-2014-3954/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-4304](https://insights.sbomify.com/CVE-2006-4304/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-0226](https://insights.sbomify.com/CVE-2006-0226/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0002](https://insights.sbomify.com/CVE-2004-0002/): Denial of service in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101304 and fix it if it is affected.

What it is: CVE-2026-101304 is a high-severity vulnerability in Freebsd Freebsd, published on 15 Oct 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-2026-101304 in the wild and no public exploit code.

Affected product: Freebsd Freebsd. 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-2026-101304/ (Markdown: https://insights.sbomify.com/CVE-2026-101304/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101304
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101304
- OSV: https://osv.dev/vulnerability/CVE-2026-101304

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101304/
Summaries are generated and may contain mistakes; the official description above is the record.