CVE-2026-58394 OPNsense: Stored XSS in Administration Settings via Certificate Description
An attacker with certificate management privileges can inject malicious scripts into certificate descriptions, leading to code execution when administrators view settings.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-58394?
CVE-2026-58394 is a medium-severity cross-site scripting vulnerability in opnsense core, published on 15 Oct 2026. An attacker needs administrator access to exploit it, 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, src/www/system_advanced_admin.php reads certificate records into $a_cert but omits that array from legacy_html_escape_form_data() before rendering each certificate descr value in the SSL Certificate selector. The certificate description accepts HTML metacharacters, allowing a user with the page-system-certmanager privilege to store markup that executes when another user opens System Settings Administration. This issue is fixed in version 26.1.11.
Weakness: CWE-79
Which versions are affected by CVE-2026-58394?
How do I fix CVE-2026-58394?
No fix has been published for CVE-2026-58394 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-2026-58394 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58394 exists.
Sources
Also known as GHSA-8pgr-x852-qx4j.