Medium severity · published Jul 2, 2026
CVE-2026-13376
WatchGuard Firebox Stored Cross-Site-Scripting (XSS) Vulnerability in spamBlocker Module
4.8
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 19% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
Fireware OS · WatchGuard
2025.1 before 2026.2.1; 12.0 before 12.12.1; 12.0 before 12.11.9; 12.0 before 12.5.19 · source: vendor
FI
Fireware · Watchguard
12.0 before 12.12.1; 2025.1 before 2026.2.1; 12.5 through 12.5.18 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-13376
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-13376
psirt.watchguard.com
https://psirt.watchguard.com/CVE-2026-13376
Vendor Advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00018
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