CVE-2026-91122 — HIGH (8.7)

Vulnerability Description

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting privileges could store the crafted placeholder in a post. When another user opened the post and clicked the video play overlay, the handler could execute arbitrary JavaScript in the viewer's session. Default Content Security Policy settings block inline event handlers, but instances with CSP disabled or relaxed could allow the script to read page content and make authenticated requests as the viewer. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.

CVSS Score

8.7

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-79

References

FAQ

What is CVE-2026-91122?

CVE-2026-91122 is a vulnerability with a CVSS score of 8.7 (HIGH). Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an ...

How severe is CVE-2026-91122?

CVE-2026-91122 has been rated HIGH with a CVSS base score of 8.7/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-91122?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.