CVE-2026-86440
MISP Dashboard Button Widget Allows Stored XSS via Unsafe javascript: and Backslash URLs
- State
- Published
- Severity
- 5.1 Medium
- Published
- Sep 7, 2026
- Updated
- Sep 8, 2026
- Reserved
- Sep 7, 2026
Description
Affected versions of MISP insufficiently validate URLs used by dashboard widgets, particularly the Button widget.
The widget's URL is stored configuration controlled by a user. The previous renderer considered a URL safe if it appeared relative or if its parsed hostname matched the configured MISP hostname. That logic failed to reject dangerous schemes and URL forms that browsers normalize differently from PHP's URL parsing.
As a result, values such as javascript: URLs or backslash-based authority forms could reach the generated anchor's href and execute script or navigate to an attacker-controlled origin when another user interacted with the widget. The upstream commit describes the issue as:
“javascript: and backslash URLs reached the href (stored XSS)”.
The fix routes widget URLs through a shared DashboardURLValidator, rejects dangerous schemes, raw backslashes, control characters, and unauthorized absolute origins, and validates the URL both in the widget handler and renderer.
Version affected: ≤2.5.45
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.1 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N | CIRCL |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
MISPMISP |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.