CVE-2026-58394: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in opnsense core
Description
A cross-site scripting (XSS) vulnerability exists in OPNsense core prior to version 26.1.11. The vulnerability occurs because certificate descriptions are not properly escaped before rendering, allowing users with the page-system-certmanager privilege to inject HTML markup. This markup executes when another user with access opens the System Settings Administration page. The issue is fixed in version 26.1.11.
CVSS v3.1
Score 5.2medium
Affected software
opnsense
core
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
OPNsense core versions before 26.1.11 have an improper neutralization of input vulnerability (CWE-79) in the src/www/system_advanced_admin.php file. Specifically, certificate descriptions are read into an array that is not passed through legacy_html_escape_form_data() before rendering in the SSL Certificate selector. This allows a user with the page-system-certmanager privilege to store HTML markup that executes when another user opens the System Settings Administration page. This cross-site scripting vulnerability is addressed in version 26.1.11.
Potential Impact
An attacker with the page-system-certmanager privilege can inject HTML markup into certificate descriptions, which executes in the context of other users when they access the System Settings Administration page. This can lead to the disclosure of sensitive information (confidentiality impact is high) and limited integrity impact. There is no impact on availability. Exploitation requires privileges and user interaction.
Mitigation Recommendations
Upgrade OPNsense core to version 26.1.11 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-30T18:19:58.378Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad0f6002cdf04f65641fe1a
Added to database: 10/15/2026, 15:49:20 UTC
Last enriched: 10/15/2026, 16:03:42 UTC
Last updated: 10/15/2026, 16:08:16 UTC
Views: 5
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.