XSS in Discourse
CVE-2025-54411
Discourse is an open-source discussion platform. Welcome banner user name string for logged in users can be vulnerable to XSS attacks, which affect the user themselves or an admin impersonating them. Admins can temporarily alter the welcome_banner.header.logged_in_members site text to remove the preferred_display_name placeholder, or not impersonate any users for the time being. This vulnerability is fixed in 3.5.0.beta8.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.002 (9.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 9.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Discourse — versions < 3.5.0.beta8, 3.5.0
Weakness classification (CWE)
References
- github.com/discourse/discourse/security/advisories/GHSA-5mm6-j5vq-6884 (Third Party Advisory, Mitigation)
- github.com/discourse/discourse/commit/a3374d2850f07444d113216e1d539ee21650dbff (Patch)
Frequently asked questions
- What is CVE-2025-54411?
- CVE-2025-54411 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2025-08-19.
- How severe is CVE-2025-54411?
- Medium severity. CVSS v3 base score is 5.4 out of 10.