The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
- An authenticated MISP user with the ability to create or modify an event graph entry.
- A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
- Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
- Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
Analysis and contextual insights are available on OpenCVE Cloud.
Vendor Solution
The vulnerability is remediated by enforcing strict server-side validation of the preview image field, restricting it to a well-formed base64-encoded PNG data URL, and by replacing the client-side string-concatenation rendering with DOM-based attribute assignment that does not interpret the value as HTML.
Tracking
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| Link | Providers |
|---|---|
| https://github.com/MISP/MISP/commit/92c7ccc43 |
|
Wed, 30 Sep 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 30 Sep 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature. The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script. Preconditions: - An authenticated MISP user with the ability to create or modify an event graph entry. - A second user (the victim) who views the event graph and triggers the preview popover. Impact: - Execution of arbitrary JavaScript in the victim's browser within the MISP application context. - Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser. - Potential for performing actions on behalf of the victim within the MISP application. Affected: MISP versions prior to the fix (commit applied after v2.5.48). | |
| Title | MISP Stored Cross-Site Scripting (XSS) via Unvalidated Event Graph Preview Image | |
| First Time appeared |
Misp
Misp misp |
|
| Weaknesses | CWE-20 CWE-79 |
|
| CPEs | cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Misp
Misp misp |
|
| References |
| |
| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: CIRCL
Published:
Updated: 2026-09-30T12:44:22.064Z
Reserved: 2026-09-30T12:18:54.232Z
Link: CVE-2026-103321
Updated: 2026-09-30T12:44:18.422Z
Status : Deferred
Published: 2026-09-30T13:17:18.463
Modified: 2026-09-30T13:17:18.603
Link: CVE-2026-103321
No data.
OpenCVE Enrichment
Updated: 2026-09-30T13:45:16Z