CVE-2026-13377

WatchGuard Firebox Stored Cross-Site-Scripting (XSS) Vulnerability in SIP Proxy Configuration

At a glance

Severity: MEDIUM 4.8
EPSS: EPSS 0.27 % · percentile 19 (2026-10-27)
State: PUBLISHED
Published: 2026-07-02
Updated: 2026-08-27
Assigner: WatchGuard
NVD status: Modified

Description

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in WatchGuard Fireware OS SIP Proxy module allows Stored XSS. This vulnerability is an additional unmitigated attack path for CVE-2025-6947.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N	WatchGuard
CVSS 4.0	MEDIUM 4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · 5d1c2695-1a31-4499-88ae-e847036fd7e3 (Secondary)
CVSS 3.1	MEDIUM 4.8	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-79

European references

ENISA EUVD · EUVD-2026-41452
GCVE · GCVE-0-2026-13377

Affected configurations (NVD CPE)

cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:* ≥ 12.0 < 12.12.1
cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:* ≥ 2025.1 < 2026.2.1
cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:* ≥ 12.5 ≤ 12.5.18

Affected products

Product	Versions
WatchGuard · Fireware OS	affected 12.0 < 12.11.9
WatchGuard · Fireware OS	affected 2025.1 < 2026.2.1 ; affected 12.0 < 12.12.1
WatchGuard · Fireware OS	affected 12.0 < 12.5.19

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD