CVE-2026-58394: XSS (CVSS 5.2)

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.

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CVSS v3.1 Score

5.2

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

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

Frequently Asked Questions

What is CVE-2026-58394? +

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. It has a CVSS v3.1 base score of 5.2 (MEDIUM).

How severe is CVE-2026-58394? +

CVE-2026-58394 has a CVSS v3.1 score of 5.2 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-58394? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-58394