Medium severity · published Oct 2, 2026
CVE-2026-104900
MISP Stored XSS via Unescaped Count Field Value in Remote Event Preview Index
5.3
CVSS
0.4%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MI
MISP · MISP
before 2.5.48 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104900
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-104900
patch
https://github.com/MISP/MISP/commit/2a2981a27
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