CVE-2026-104907 MISP: JavaScript Injection via Remote Tag ID in Event Preview Inline Handler
Attackers can execute arbitrary JavaScript in MISP users' browsers via malicious tag IDs from linked servers, requiring remote server configuration.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-104907?
CVE-2026-104907 is a medium-severity cross-site scripting vulnerability in MISP, published on 2 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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).
Which versions are affected by CVE-2026-104907?
How do I fix CVE-2026-104907?
No fix has been published for CVE-2026-104907 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-104907 being exploited?
There is no known exploitation of CVE-2026-104907 in the wild and no public exploit code.
Sources
Also known as GHSA-4g8m-xfv2-jhr3.