# CVE-2026-45252: Heap overflow in FUSE_LISTXATTR

> A malicious FUSE daemon can trigger a heap overflow in the FreeBSD kernel, potentially disclosing memory or executing code.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 May 2026
- **Updated:** 21 May 2026
- **Also known as:** GHSA-fqrg-fvv5-42g2

## What is CVE-2026-45252?

CVE-2026-45252 is a medium-severity memory corruption vulnerability in Freebsd Freebsd, published on 21 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

When a fusefs file system implements extended attributes, the kernel may send a FUSE_LISTXATTR message to the userspace daemon to retrieve the list of extended attributes for a given file.  The FUSE protocol requires the daemon to return a packed list of NUL-terminated strings.  The fusefs kernel module calls strlen() on this daemon-supplied buffer without first verifying that the entire list is NUL-terminated.

If a malicious daemon sends a non-NUL-terminated list, the fusefs kernel module may read beyond the end of one heap-allocated buffer and potentially write beyond the end of a second buffer.  A malicious daemon could disclose up to 253 bytes of kernel heap memory, or it could inject up to 250 attacker-controlled bytes into unallocated kernel heap space.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-45252?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-45252?

No fix has been published for CVE-2026-45252 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-45252 being exploited?

There is no known exploitation of CVE-2026-45252 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-2026-45252 and fix it if it is affected.

What it is: CVE-2026-45252 is a medium-severity memory corruption vulnerability in Freebsd Freebsd, published on 21 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-45252 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-2026-45252/ (Markdown: https://insights.sbomify.com/CVE-2026-45252/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45252
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45252
- OSV: https://osv.dev/vulnerability/CVE-2026-45252

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45252/
Summaries are generated and may contain mistakes; the official description above is the record.