XSS in Discourse

CVE-2024-35234

Discourse is an open-source discussion platform. Prior to version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch, an attacker can execute arbitrary JavaScript on users’ browsers by posting a specific URL containing maliciously crafted meta tags. This issue only affects sites with Content Security Polic (CSP) disabled. The problem has been patched in version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch. As a workaround, ensure CSP is enabled on the forum.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L.

EPSS exploit prediction

EPSS: 0.003 (24.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 24.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2024-35234: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Discourse — versions tests-passed < 3.3.0.beta3, stable < 3.2.3, 3.3.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2024-35234?
CVE-2024-35234 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 4.2/10. Published 2024-07-03.
How severe is CVE-2024-35234?
Medium severity. CVSS v3 base score is 4.2 out of 10.