# CVE-2026-13371: WatchGuard Firebox Management Web UI Denial of Service via Unsafe Deserialization

> An authenticated administrator can cause a denial of service in WatchGuard Firebox management by sending crafted data to an unsafe deserialization endpoint.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Jul 2026
- **Updated:** 27 Aug 2026
- **Also known as:** GHSA-hprc-6hj7-jj8j

## What is CVE-2026-13371?

CVE-2026-13371 is a medium-severity unsafe deserialization vulnerability in Watchguard Fireware, published on 2 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-13371?

It affects 1 product.


Products: Watchguard Fireware.

## How do I fix CVE-2026-13371?

No fix has been published for CVE-2026-13371 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13371 being exploited?

There is no known exploitation of CVE-2026-13371 in the wild and no public exploit code.

## Other vulnerabilities in Watchguard Fireware

- [CVE-2022-26318](https://insights.sbomify.com/CVE-2022-26318/): WatchGuard Firebox and XTM Appliances Arbitrary Code Execution (critical 9.8, exploited in the wild)
- [CVE-2025-14733](https://insights.sbomify.com/CVE-2025-14733/): WatchGuard Firebox Out of Bounds Write (critical 9.3, exploited in the wild)
- [CVE-2025-9242](https://insights.sbomify.com/CVE-2025-9242/): WatchGuard Firebox Out-of-Bounds Write (critical 9.3, exploited in the wild)
- [CVE-2022-23176](https://insights.sbomify.com/CVE-2022-23176/): WatchGuard Firebox and XTM Privilege Escalation (high 8.8, exploited in the wild)
- [CVE-2022-31789](https://insights.sbomify.com/CVE-2022-31789/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13371 and fix it if it is affected.

What it is: CVE-2026-13371 is a medium-severity unsafe deserialization vulnerability in Watchguard Fireware, published on 2 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13371 in the wild and no public exploit code.

Affected product: Watchguard Fireware. 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-2026-13371/ (Markdown: https://insights.sbomify.com/CVE-2026-13371/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13371
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13371
- OSV: https://osv.dev/vulnerability/CVE-2026-13371

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-13371/
Summaries are generated and may contain mistakes; the official description above is the record.