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Fencer Vulns
medium 4.8

CVE-2026-104907 json

MISP: JavaScript Injection via Remote Tag ID in Event Preview Inline Handler

published 2026-10-02 38 d ago modified 2026-10-02 38 d ago also EUVD-2026-91743

cvss
4.8
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

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).

Patch / fix

  • MISP MISP 2.5.48

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
38 d ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 4.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
CNA 4.0 4.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • MISP MISP

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-116 Improper Encoding or Escaping of Output

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.