# CVE-2026-103594: Fireware OS Stack Buffer Overflow in WireGuard Configuration Allows Remote Code Execution


- **Severity:** Critical 9.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** GHSA-69hq-vhp9-m5w6

## What is CVE-2026-103594?

CVE-2026-103594 is a critical vulnerability in WatchGuard Fireware OS, published on 27 Oct 2026. 

### Official description

A stack-based buffer overflow vulnerability in Fireware OS's WireGuard configuration processing allows a remote attacker that has man-in-the-middle TLS-decrypted access between the Firebox and WatchGuard Cloud to create a Denial of Service condition and potentially execute arbitrary code by tampering with a FireCloud Gateway configuration payload.

Weakness: CWE-787 (Out-of-bounds Write), CWE-1284 (Improper Validation of Specified Quantity in Input), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-103594?


## How do I fix CVE-2026-103594?

No fix has been published for CVE-2026-103594 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103594 being exploited?

There is no known exploitation of CVE-2026-103594 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103594 and fix it if it is affected.

What it is: CVE-2026-103594 is a critical vulnerability in WatchGuard Fireware OS, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-103594 in the wild and no public exploit code.

Affected product: WatchGuard Fireware OS. 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-2026-103594/ (Markdown: https://insights.sbomify.com/CVE-2026-103594/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103594
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103594
- OSV: https://osv.dev/vulnerability/CVE-2026-103594

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103594/
Summaries are generated and may contain mistakes; the official description above is the record.