# CVE-2026-86101 — WatchGuard Fireware OS

> As of 2026-09-30, CVE-2026-86101 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 7.2, EPSS 0.2% (11.6th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-86101, most recently “WatchGuard Fireware OS Critical Code Injection Vulnerability in BOVPN over TLS Client (CVE-2026-86131)”.

**Last updated:** 2026-09-30

## What is CVE-2026-86101?

An improper authorization vulnerability in WatchGuard Fireware OS's SAML login process allows a remote, authenticated SAML user with access only to the Access Portal to obtain unauthorized Mobile VPN with SSL access through a specially crafted request.

The record classifies CVE-2026-86101 under weakness classes [CWE-285](https://intel.threadlinqs.com/cwe/CWE-285), [CWE-863](https://intel.threadlinqs.com/cwe/CWE-863). 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:** 7.2 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:H/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 11.6% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-29, last modified 2026-09-30

## Is CVE-2026-86101 being exploited?

It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

## Affected products and versions

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

## How to fix CVE-2026-86101

No vendor patch reference has been recorded for CVE-2026-86101 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-2026-86101

1 tracked threat in the Threadlinqs corpus references CVE-2026-86101, 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, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [psirt.watchguard.com — vendor advisory](https://psirt.watchguard.com/CVE-2026-86101)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-86101
Full detection coverage and IOCs for threats exploiting CVE-2026-86101 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp