CVE-2026-104900 MISP Stored XSS via Unescaped Count Field Value in Remote Event Preview Index
Stored XSS in MISP allows attackers to execute arbitrary JavaScript in victim sessions via crafted remote event identifiers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-104900?
CVE-2026-104900 is a medium-severity cross-site scripting vulnerability in MISP, published on 2 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
MISP contains a stored cross-site scripting (XSS) vulnerability in the index table rendering of the remote event preview. The count field template escaped the associated link URL but rendered the field value without HTML encoding. An attacker with the ability to create or modify events on a linked (remote) MISP server could craft an event identifier containing HTML or JavaScript markup. When a user on the local MISP instance views the remote event preview index, the unescaped value is rendered directly in the browser, allowing arbitrary script execution in the victim's session.
Preconditions:
- A linked/remote MISP server is configured and connected to the local instance.
- The attacker has sufficient access on the linked server to create or modify an event with a crafted identifier.
- A victim user on the local instance views the remote event preview index page.
Impact:
- Execution of arbitrary JavaScript in the context of the MISP web application.
- Potential session hijacking, data exfiltration, or unauthorized actions performed on behalf of the authenticated user.
Affected versions: <2.5.48.
Weakness: CWE-79
Which versions are affected by CVE-2026-104900?
How do I fix CVE-2026-104900?
No fix has been published for CVE-2026-104900 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-2026-104900 being exploited?
There is no known exploitation of CVE-2026-104900 in the wild and no public exploit code.
Sources
Also known as GHSA-7mf5-g482-f646.