CVE-2026-103664 MISP Reflected Cross-Site Scripting via Unsanitized Analyst Data Seed Parameter
Reflected XSS in MISP allows attackers to execute arbitrary JavaScript in authenticated users' browsers via a crafted URL, potentially stealing session tokens.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-103664?
CVE-2026-103664 is a medium-severity cross-site scripting vulnerability in MISP, published on 1 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
MISP contains a reflected cross-site scripting (XSS) vulnerability in the analyst data notes panel. The seed path parameter, supplied by the user via the URL, was passed directly into inline JavaScript within the rendered HTML response without any sanitization or type enforcement.
An attacker who can convince an authenticated MISP user to navigate to a crafted URL (for example, via a phishing link) can inject arbitrary JavaScript that executes in the victim's browser context. This may allow the attacker to read session tokens, manipulate the page, or perform actions on behalf of the victim.
Preconditions:
- The victim must be authenticated to MISP and access the analyst data view for an attribute or object.
- The attacker must supply a malicious seed value in the URL path.
Impact:
- Execution of arbitrary JavaScript in the victim's browser session.
- Potential theft of session credentials or sensitive data visible in the page.
- Manipulation of the analyst data interface.
Affected: MISP versions prior to the fix (commit 58925dbf0, post v2.5.48).
Weakness: CWE-79
Which versions are affected by CVE-2026-103664?
How do I fix CVE-2026-103664?
No fix has been published for CVE-2026-103664 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-103664 being exploited?
There is no known exploitation of CVE-2026-103664 in the wild and no public exploit code.
Sources
Also known as GHSA-66pp-jmhc-r9mv.