CVE-2026-86440
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.
Does this matter?
Lower severity and a low EPSS score (0.14%). Track it; it rarely justifies an emergency change on its own.
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
- CVSS 4.0
- 5.1 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.14% probability · 4th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20, CWE-79
- Affected
- misp-project/misp
- Source
- 5a6e4751-2f3f-4070-9419-94fb35b644e8
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.