# CVE-2026-103321: MISP stored cross-site script in event graph preview

Source: https://junglewise.ai/threats/cve-2026-103321-misp-contains-a-stored-cross-site-script-xss-vulnerability-in  
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-2026-103321 · Severity: info · Published 2026-09-30

MISP is an open-source threat intelligence platform used to share and analyze security threat information. An attacker with user authentication can inject malicious code into event graph preview fields that executes in the browsers of other users viewing those graphs, potentially stealing their session tokens or performing unauthorized actions on their behalf.

Technologies: [Misp](https://junglewise.ai/threats/technologies/misp). Vendors: [Misp](https://junglewise.ai/threats/vendors/misp).

## Quick answers

**Is CVE-2026-103321 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-103321 being exploited in the wild.

**How severe is CVE-2026-103321?** Informational severity, published 30 September 2026.

**Which products and versions are affected?** Misp prior to v2.5.48.

**Is there a fix for CVE-2026-103321?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-103321 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-103321?** Check whether you run 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

A stored XSS vulnerability exists in the event graph preview feature where the preview image field accepts unvalidated user input and renders it directly into an HTML img src attribute via string concatenation. The vulnerability requires an authenticated attacker with event creation/modification permissions and a victim user to view the malicious graph preview. The fix validates input as base64 PNG data URLs and constructs the DOM element safely instead of via string concatenation.

## Affected products

- MISP MISP prior to v2.5.48

## Timeline

- 2026-09-30: disclosed: CVE-2026-103321 published

## References

- [https://github.com/MISP/MISP/commit/92c7ccc43](https://github.com/MISP/MISP/commit/92c7ccc43)

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- [MISP reflected XSS in taxonomy tag confirmation forms](https://junglewise.ai/threats/cve-2026-103662-misp-contains-a-reflected-cross-site-scripting-xss-vulnerability)