CVE-2026-58394

OPNsense: Stored XSS in Administration Settings via Certificate Description

5.2 Medium

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: Low
Availability: None

Exploit likelihood

0.24%Unchanged since Oct 16, 2026

What each source reports

CVE List Score used 5.2

OPNsense: Stored XSS in Administration Settings via Certificate Description

Record: CVE-2026-58394
CVSS 3.1: 5.2 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2026-102135 5.2

Record: EUVD-2026-102135
CVSS 3.1: 5.2 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N
Updated: 2026-11-02

NVD 5.2

Record: CVE-2026-58394
CVSS 3.1: 5.2 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSV 5.2

OPNsense: Stored XSS in Administration Settings via Certificate Description

Record: CVE-2026-58394
CVSS 3.1: 5.2 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

opnsense core

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-58394 is a medium vulnerability (CVSS 5.2) in Opnsense Core, published October 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. No source names a fixed version.