# CVE-2026-13046 — WatchGuard Fireware OS

> As of 2026-10-01, CVE-2026-13046 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in WatchGuard Fireware OS, CVSS v4.0 7.5, EPSS 0.3% (28.8th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-13046, most recently “WatchGuard Fireware OS Critical Code Injection Vulnerability in BOVPN over TLS Client (CVE-2026-86131)”.

**Last updated:** 2026-10-01

## What is CVE-2026-13046?

A deserialization of untrusted data vulnerability in WatchGuard Fireware OS's SAML single sign-on session handling (samld) allows an attacker who has already obtained the ability to write files on the appliance to execute arbitrary code in the context of the samld service by causing samld to load a maliciously crafted session file.

The record classifies CVE-2026-13046 under weakness class [CWE-502](https://intel.threadlinqs.com/cwe/CWE-502). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 25 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 7.5 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 28.8% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-29, last modified 2026-10-01

## Is CVE-2026-13046 being exploited?

It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [WatchGuard](https://intel.threadlinqs.com/vendors/watchguard): Fireware OS

## How to fix CVE-2026-13046

No vendor patch reference has been recorded for CVE-2026-13046 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-13046

1 tracked threat in the Threadlinqs corpus references CVE-2026-13046, either in the campaign’s CVE list or as an indicator on the campaign record.

- [WatchGuard Fireware OS Critical Code Injection Vulnerability in BOVPN over TLS Client (CVE-2026-86131)](https://intel.threadlinqs.com/threat/TL-2026-2813) — CRITICAL · 2026-09-30

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [psirt.watchguard.com — vendor advisory](https://psirt.watchguard.com/CVE-2026-13046)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-13046
Full detection coverage and IOCs for threats exploiting CVE-2026-13046 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp