CVE-2026-58394Public exploitNetwork attack vector

Stored XSS via unescaped certificate descriptions

Published Oct 15, 2026 · Updated Oct 15, 2026

Stored XSS in OPNsense Core before 26.1.11 allows remote authenticated users to run scripts via certificate descriptions. In src/www/system_advanced_admin.php, the SSL Certificate selector renders certificate descr values without passing $a_cert through legacy_html_escape_form_data(), although descriptions accept HTML metacharacters. Exploitation requires certificate-management privileges and another user opening System Settings Administration; injected scripts execute in that user's GUI session.

CVSS severity5.2
Medium
EPSS probability0.24%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in OPNsense Core before 26.1.11 allows remote authenticated users to run scripts via certificate descriptions. In src/www/system_advanced_admin.php, the SSL Certificate selector renders certificate descr values without passing $a_cert through legacy_html_escape_form_data(), although descriptions accept HTML metacharacters. Exploitation requires certificate-management privileges and another user opening System Settings Administration; injected scripts execute in that user's GUI session.

The record

CVE
CVE-2026-58394
Published
Oct 15, 2026
Updated
Oct 15, 2026
Vendor
OPNsense
Product
OPNsense Core
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 26.1.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OPNsense · OPNsense Coreversion=< 26.1.11

Published CVSS scores

5.2GitHub_MCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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