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CVE-2026-104907

MISP: JavaScript Injection via Remote Tag ID in Event Preview Inline Handler

MISP MISP
Open in ThreatlineRecord JSON
CVSS
4.8Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.35%Chance of exploitation activity in the next 30 days, higher than 27% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2.5.48Fixed versionCVE List
Published2 Oct 2026Updated 2 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

MISP contains a cross-site scripting (XSS) vulnerability in the remote event preview page. When a linked (remote) MISP server is configured, the event preview renders tag identifiers inside an inline JavaScript onclick attribute. The tag ID value was HTML-escaped but not sanitized for the JavaScript string context, meaning a malicious linked server could supply a tag ID containing characters (such as a single quote) that break out of the JavaScript string literal and inject arbitrary script.

Preconditions:

  • A linked/remote MISP server is configured and connected to the local instance.
  • The linked server supplies a crafted tag ID in an event.
  • An authenticated user views the event preview and interacts with the affected tag element.

Impact:

  • Arbitrary JavaScript execution in the context of the viewing user's browser session, potentially allowing session hijacking, data exfiltration, or unauthorized actions on behalf of the user.

Affected versions: MISP prior to the fix commit (v2.5.48 or later, exact boundary unconfirmed).

Text from CVE List

Affected versions 1

  • MISPaffected: all versions before 2.5.48CVE List

References 1