CVE-2026-13376: WatchGuard Fireware OS · Cross-site Scripting
Affects WatchGuard Fireware OSSource CVE Database V5
Mentioned vulnerabilities
Not known to be exploited · CVSS 4.8 Medium : upgrade to 2026.2.1 or 12.12.1 when convenient.
Data as of 14 Nov 2026, 20:44 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2026.2.1, 12.12.1, 12.11.9 +1
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 2 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.
What to do
Upgrade Fireware to 2026.2.1 or 12.12.1 (OS); 12.11.9 (OS); 12.5.19 (OS).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| WatchGuardFireware OS | Affected
| Fixed in
|
| WatchGuardFireware OS | Affected
| Fixed in
|
| WatchGuardFireware OS | Affected
| Fixed in
|
| WatchGuardFireware OS | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, limit access to the Fireware OS management interface to trusted administrators and monitor for suspicious activity related to the spamBlocker module. Avoid exposing the management interface to untrusted networks.
Description
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in WatchGuard Fireware OS spamBlocker module allows Stored XSS. This vulnerability is an additional unmitigated attack path for CVE-2025-1071. This issue affects Fireware OS 12.0 up to and including 12.12, 12.5 up to and including 12.5.18, and 2025.1 up to and including 2026.2.