HIGH

CVE-2026-91122

CVSS v3

8.7

HIGH

EPSS Score

0.3 %

exploit probability, as of 2026-09-28

CISA KEV

known exploited

Exploitation

—

SSVC status

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 Co

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Published: 2026-09-24
Last Modified: 2026-09-24

Frequently asked questions

What is CVE-2026-91122?

Is CVE-2026-91122 actively exploited?

Active exploitation of CVE-2026-91122 has not been confirmed. Its EPSS score was 0.3% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-91122?

CVE-2026-91122 has a CVSS v3 base score of 8.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.

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