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CVE-2026-103388

MISP Stored Cross-Site Scripting via JavaScript URL in Galaxy Cluster Source Field

MISP MISP
Open in ThreatlineRecord JSON
CVSS
6.2Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.24%Chance of exploitation activity in the next 30 days, higher than 14% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2.5.48Fixed versionCVE List
Published30 Sep 2026Updated 30 Sep 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 renders the source field of a Galaxy Cluster as a clickable hyperlink whenever the stored value passes PHP's FILTER_VALIDATE_URL validation. Because FILTER_VALIDATE_URL accepts the javascript: URI scheme, a user with galaxy editor privileges on the local instance or on a synced instance could store a javascript: URL as the cluster source.

When another user views the affected Galaxy Cluster and clicks the rendered link, the embedded script executes in the victim's browser context, enabling session hijacking, data exfiltration, or actions performed on behalf of the victim.

Preconditions:

  • Attacker must hold galaxy editor privileges (local or via sync).
  • Victim must view the affected cluster and click the malicious link.

Impact:

  • Stored cross-site scripting (XSS) in the victim's browser.
  • Potential session theft, credential harvesting, or unauthorized actions within the MISP application.

Affected: <2.5.48.

Text from CVE List

Affected versions 1

  • MISPaffected: all versions before 2.5.48CVE List

References 1