Cross-site scripting in OPNsense - #VU142554
Published: August 14, 2026
Vulnerability identifier: #VU142554
CSH Severity: Low
CVSS v4: 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]
CVE-ID: N/A
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary JavaScript in the victim\'s browser.
The vulnerability exists due to cross-site scripting in Traffic Shaper relation description tooltip rendering in Firewall Rules when constructing HTML attributes from stored shaper descriptions. A remote privileged user can modify a referenced shaper object\'s description with a specially crafted value to execute arbitrary JavaScript in the victim\'s browser.
User interaction is required to hover the gear icon, and exploitation additionally requires that a firewall rule already reference the affected pipe or queue.
Affected software
OPNsense
Remediation
Install security update from vendor's website.
OPNsense - update to 26.7.2