Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M

CVE-2026-58394OPNsense: Stored XSS in Administration Settings via Certificate Description

Medium 5.2

In plain English

A medium-severity cross-site scripting in core from opnsense. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).

Severity (CVSS 3.1)5.2Medium

Exploit odds (30 days)0.2%top 84.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
opnsense	core	< 26.1.11

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N

References

https://github.com/opnsense/core/security/advisories/GHSA-8pgr-x852-qx4j x_refsource_CONFIRM
https://github.com/opnsense/core/commit/9d0a590e9c49f4374a5539929b366123f63bc9eb x_refsource_MISC
https://github.com/opnsense/core/commit/adcb02f8f68071e636bf9660b2cb8d0229f34674 x_refsource_MISC
https://hackerask.com/posts/opnsense x_refsource_MISC