CVE-2026-104906

MISP TAXII Object Viewer Stored XSS via Unescaped JSON Output

Published Oct 2, 2026 CVSS 4.0 · 6.2 Medium EPSS < 1% KEV · Not listed
Description
MISP contains a cross-site scripting (XSS) vulnerability in the TAXII object viewer. When displaying a remote TAXII object, the JSON content of string properties was rendered directly into an HTML pre block without HTML-encoding. An attacker who can control or influence the content of a TAXII object (e.g., by publishing a malicious object to a TAXII server that the victim's MISP instance subscribes to) can inject arbitrary HTML or JavaScript that executes in the context of the victim's MISP session.

Preconditions:

- The victim must be an authenticated MISP user with access to the TAXII object viewer.

- The victim must open or view the crafted TAXII object.

Impact:

- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.

- Potential theft of session tokens, API keys, or other sensitive data accessible from the MISP interface.

- Potential for performing actions on behalf of the authenticated user.

Affected versions: <2.5.48.

Remediation

Vendor Solution

The fix applies HTML-encoding (via the h() helper) to the JSON string before it is interpolated into the HTML pre element. This ensures that any HTML or script markup present in the JSON string properties of a TAXII object is rendered as inert text rather than being parsed and executed by the browser, eliminating the XSS vector.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description MISP contains a cross-site scripting (XSS) vulnerability in the TAXII object viewer. When displaying a remote TAXII object, the JSON content of string properties was rendered directly into an HTML pre block without HTML-encoding. An attacker who can control or influence the content of a TAXII object (e.g., by publishing a malicious object to a TAXII server that the victim's MISP instance subscribes to) can inject arbitrary HTML or JavaScript that executes in the context of the victim's MISP session. Preconditions: - The victim must be an authenticated MISP user with access to the TAXII object viewer. - The victim must open or view the crafted TAXII object. Impact: - Execution of arbitrary JavaScript in the victim's browser within the MISP application context. - Potential theft of session tokens, API keys, or other sensitive data accessible from the MISP interface. - Potential for performing actions on behalf of the authenticated user. Affected versions: <2.5.48.
Title MISP TAXII Object Viewer Stored XSS via Unescaped JSON Output
First Time appeared Misp
Misp misp
Weaknesses CWE-79
CPEs cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*
Vendors & Products Misp
Misp misp
References
Metrics cvssV4_0

{'score': 6.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Oct 2, 2026, 4:17 PM
Reserved
Oct 2, 2026, 3:49 PM
Status
Deferred
Published
Oct 2, 2026, 4:16 PM
Modified
Oct 2, 2026, 5:17 PM