Vulnerability · Published Oct 27, 2026 · Assigned by WatchGuard
CVE-2026-90442Fireware OS Authenticated Stack Buffer Overflow in certd Allows Denial of Service
High 8.6
In plain English
A high-severity stack buffer overflow 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 0.2% (higher than 16% of all known vulnerabilities).
Severity (CVSS 4.0)8.6High
Exploit odds (30 days)0.2%top 84.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A stack-based buffer overflow vulnerability in the Fireware OS certd process allows an authenticated attacker with access to the Firebox management interface to crash the certificate management service and potentially execute arbitrary code by sending a specially crafted request.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| WatchGuard | Fireware OS | 2025.1 – before 2026.412.0 – before 12.12.4 |
| WatchGuard | Fireware OS | 12.0 – before 12.5.22 |
Weakness: CWE-121, CWE-787 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
References
- https://psirt.watchguard.com/CVE-2026-90442 vendor-advisory