Cross-site scripting in OPNsense - #VU139367
Published: July 26, 2026
Vulnerability identifier: #VU139367
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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 script in the victim's browser within the WebGUI origin.
The vulnerability exists due to cross-site scripting in the firewall live view label rendering in /ui/diagnostics/firewall/log when decoding and rendering a stored firewall rule description from log-derived state. A remote user can store a crafted firewall rule description to execute arbitrary script in the victim's browser within the WebGUI origin.
User interaction is required to open the firewall live view page, and exploitation requires a packet matching the logged rule.
Affected software
OPNsense
Remediation
Install security update from vendor's website.
OPNsense - update to 26.7.1