Vulnerability · Published Sep 30, 2026 · Assigned by WatchGuard
CVE-2026-86134Fireware OS Pre-Authentication NULL Pointer Dereference Allows Remote Denial of Service
High 8.7
In plain English
A high-severity null pointer dereference in Fireware OS from WatchGuard. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).
Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.4%top 65.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| WatchGuard | Fireware OS | 2026.3 – before 2026.3.22025.0 – before 2026.2.312.0 – before 12.12.3 |
| WatchGuard | Fireware OS | 12.0 – before 12.5.21 |
Weakness: CWE-476 · Vector: 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
References
- https://psirt.watchguard.com/CVE-2026-86134 vendor-advisory