XSS in Discourse
CVE-2026-32243
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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (6.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Discourse — versions >= 2026.3.0-latest, < 2026.3.0, >= 2026.2.0-latest, < 2026.2.2, >= 2026.1.0-latest, < 2026.1.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-32243?
- CVE-2026-32243 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-03-31.
- How severe is CVE-2026-32243?
- Medium severity. CVSS v3 base score is 5.4 out of 10.