# CVE-2026-86134: Fireware OS Pre-Authentication NULL Pointer Dereference Allows Remote Denial of Service

> Remote unauthenticated attackers can crash the management daemon via a specially crafted request to the login interface, causing denial of service.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-fhvg-p495-phcg

## What is CVE-2026-86134?

CVE-2026-86134 is a high-severity vulnerability in Watchguard Fireware, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A NULL pointer dereference vulnerability in the WatchGuard Fireware OS authentication process allows a remote, unauthenticated attacker to crash the management daemon by sending a specially request to the login interface, resulting in a denial of service.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-86134?

It affects 1 product.


Products: Watchguard Fireware.

## How do I fix CVE-2026-86134?

No fix has been published for CVE-2026-86134 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-86134 being exploited?

There is no known exploitation of CVE-2026-86134 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-2026-86134 and fix it if it is affected.

What it is: CVE-2026-86134 is a high-severity vulnerability in Watchguard Fireware, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-86134 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-2026-86134/ (Markdown: https://insights.sbomify.com/CVE-2026-86134/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86134
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86134
- OSV: https://osv.dev/vulnerability/CVE-2026-86134

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86134/
Summaries are generated and may contain mistakes; the official description above is the record.