CVE Catalog

CVE-2026-58391

MediumCVSS 5.4
Published: Translated: NVD NIST

Summary

In OPNsense prior to version 26.1.11, Firewall Rules and NAT views place stored category names and alias descriptions into HTML title attributes without quote-safe encoding. The response layer uses ENT_NOQUOTES, so a double quote survives and closes the attribute, allowing an event-handler attribute to be added to the existing span. A user with Firewall Categories or Firewall Alias Edit privileges can store a malicious value that executes script in the session of an administrator opening the affected Rules or NAT page.

Risk Assessment

An authenticated user with limited privileges can execute arbitrary script in an administrator's session, access CSRF material, and perform authenticated actions as the victim. This leads to privilege escalation and full compromise of the firewall configuration.

Recommendation

Upgrade OPNsense to version 26.1.11 or later. Until patched, restrict Firewall Categories and Alias Edit privileges to trusted administrators only.

Other vulnerabilities in OPNsense

See all
Original NVD description (English source)

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, Firewall Rules and NAT views place stored category names and alias descriptions into HTML title attributes in filter_rule.volt and nat_rule.volt without quote-safe encoding. The response layer uses ENT_NOQUOTES, so a double quote survives and closes the attribute, allowing an event-handler attribute to be added to the existing span. A user with Firewall Categories or Firewall Alias Edit privileges can store a category name or alias description; the category must be assigned to a filter or NAT rule, or the alias must be referenced by a rule source or destination, and the rule must be saved so the affected tooltip is rendered. Script then executes in the session of an administrator or other user who opens the affected Rules or NAT page. The script can access CSRF material and perform authenticated actions as the victim. This issue is fixed in version 26.1.11.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS