CVE-2026-32243CWE-79

Discourse: Stored XSS in discourse-ai shared conversations onebox

Medium · published March 31, 2026

CVSS v4.0
5.3
EPSS
0%
Percentile
20.1
In the wild
Unconfirmed
What it is

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted conversation titles. This payload would execute in the browser of any user viewing the onebox preview, potentially allowing session hijacking or unauthorized actions on behalf of the victim. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

The record
Technical detail
CVSS v4.0
5.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00287 · 20.1th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-03-31T17:39Z
EPSS history
Timeline
  • 31 MAR 17:39Z
    Discourse: Stored XSS in discourse-ai shared conversations onebox
    cvelistv5