CVE-2026-58391

medium

EUVD alias: EUVD-2026-102113

Assigned by CNA: github_m

Published 2026-10-15 · Modified 2026-10-15

Discuss on Community Propose mitigation

CVSS v3

5.4

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.4

Description

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.

Predictions

Exploit likelihood

64%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

CWEs

CWE-79 CWE-83

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.