CVE-2026-58390 OPNsense: Stored XSS to root RCE via OpenVPN client common_name in status views
Stored XSS in OPNsense OpenVPN status views allows attackers to execute arbitrary code and gain root privileges if specific authentication configurations are used.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-58390?
CVE-2026-58390 is a high-severity cross-site scripting vulnerability in opnsense core, published on 15 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the OpenVPN connection-status dashboard widget in src/opnsense/www/js/widgets/OpenVPNClients.js and the connection-status view place a client common_name into data-common-name attributes without quote-safe encoding. Exploitation requires an OpenVPN server configured with username-as-common-name and RADIUS or LDAP authentication, plus the ability to provision or self-register a valid backend username containing a double quote; deployments where the same administrator controls both the identity backend and firewall do not cross a separate trust boundary. An authenticated client using that username can close the attribute and add an event handler, while the local user database is not affected because its username validator rejects quotes. Script executes in an administrator's session when the administrator opens the dashboard or connection-status page and the injected event is triggered; the demonstrated payload used pointer movement over the client row rather than unconditional page-load execution. The advisory demonstrates that the script can read config.xml, invoke privileged APIs, reset the root password, and obtain root command execution. This issue is fixed in version 26.1.11.
Weakness: CWE-79
Which versions are affected by CVE-2026-58390?
How do I fix CVE-2026-58390?
No fix has been published for CVE-2026-58390 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-58390 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58390 exists.
Sources
Also known as GHSA-26cj-h9rj-g5pf.