# CVE-2026-103388: MISP stored XSS in Galaxy Cluster source field

Source: https://junglewise.ai/threats/cve-2026-103388-misp-renders-the-source-field-of-a-galaxy-cluster-as-a-clickable  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-30. Updated: 2026-09-30  
License: CC BY 4.0 with a link back

CVE-2026-103388 · Severity: info · Published 2026-09-30

MISP, a threat intelligence platform, renders the source field of Galaxy Clusters as clickable hyperlinks. An attacker with galaxy editor privileges can inject a malicious JavaScript URL that bypasses URL validation. When another user clicks the link, the attacker's script executes in the victim's browser, potentially stealing session tokens, extracting data, or performing unauthorized actions.

Technologies: [MISP Project MISP](https://junglewise.ai/threats/technologies/misp-project-misp). Vendors: [MISP Project](https://junglewise.ai/threats/vendors/misp-project).

## Quick answers

**Is CVE-2026-103388 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-103388 being exploited in the wild.

**How severe is CVE-2026-103388?** Informational severity, published 30 September 2026.

**Which products and versions are affected?** MISP Project MISP before 2.5.48.

**Is there a fix for CVE-2026-103388?** A patch was published on 2026-09-30: Fix committed to restrict links to http(s) URLs only Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-103388 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-103388?** Check whether you run MISP Project MISP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a stored cross-site scripting (XSS) flaw in the Galaxy Cluster source field rendering. MISP uses PHP's FILTER_VALIDATE_URL for validation, which incorrectly accepts javascript: URIs as valid URLs. An authenticated attacker with galaxy editor privileges (local or via instance sync) can store a javascript: URL as the cluster source, which is then rendered as a clickable hyperlink. When a victim clicks the link, the embedded script executes with the victim's privileges, enabling session hijacking or data exfiltration.

## Affected products

- MISP Project MISP before 2.5.48

## Timeline

- 2026-09-30: disclosed: CVE-2026-103388 published
- 2026-09-30: patched: Fix committed to restrict links to http(s) URLs only

## References

- [https://github.com/MISP/MISP/commit/118528767](https://github.com/MISP/MISP/commit/118528767)

## Related threats

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- [MISP server settings information disclosure](https://junglewise.ai/threats/cve-2026-112188-misp-contains-a-vulnerability-in-its-server-settings-lookup)
- [MISP reflected XSS in workflow module interface](https://junglewise.ai/threats/cve-2026-112184-misp-contains-a-reflected-cross-site-scripting-xss-vulnerability)
- [MISP data integrity flaw in event deletion logic](https://junglewise.ai/threats/cve-2026-112180-misp-contains-a-data-integrity-flaw-in-its-event-deletion-logic)
- [MISP event synchronization information disclosure via tag filtering](https://junglewise.ai/threats/cve-2026-112179-in-misp-the-event-synchronization-process-contained-a-logic)