EUVD-2026-18320
GHSA-h6h2-h2qj-ww49
Severity by source
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/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
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
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/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
Lifecycle Timeline
3DescriptionCVE.org
Endian Firewall version 3.3.25 and prior allow stored cross-site scripting (XSS) via the REMARK parameter to /cgi-bin/openvpnclient.cgi. An authenticated attacker can inject arbitrary JavaScript that is stored and executed when other users view the affected page.
AnalysisAI
Stored cross-site scripting in Endian Firewall 3.3.25 and earlier allows authenticated attackers to inject arbitrary JavaScript via the REMARK parameter in /cgi-bin/openvpnclient.cgi, with the payload persisted and executed when other users access the affected page. CVSS 5.1 reflects low immediate impact due to user interaction requirement and limited scope, but the stored nature increases attack persistence; no public exploit code or CISA KEV confirmation identified at time of analysis.
Technical ContextAI
The vulnerability exists in the OpenVPN client configuration interface of Endian Firewall, a network security appliance. The root cause is improper input validation and output encoding of user-supplied data in the REMARK parameter passed to the openvpnclient.cgi script (CWE-79: Improper Neutralization of Input During Web Page Generation). Unlike reflected XSS, stored XSS requires the web application to persistently save unsanitized user input in a backend store (typically a database or configuration file) and then serve it to other authenticated users without proper encoding. This attack vector is particularly dangerous in administrative or management interfaces where multiple authorized users review configurations.
RemediationAI
Upgrade Endian Firewall to a patched version released after 3.3.25. Consult the vendor advisory at https://help.endian.com/hc/en-us/sections/360004371358-Community for the specific fix version and installation instructions. Until patching is completed, mitigate risk by restricting access to the Endian Firewall web administration interface to trusted IP addresses or networks via firewall rules, limiting the number of authenticated accounts with configuration access, and monitoring access logs for suspicious REMARK parameter input or XSS payload patterns. Additionally, educate administrators to avoid clicking on unexpected links or reviewing configurations from untrusted sources within the web UI.
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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