XSS in Discourse

CVE-2025-48954

Discourse is an open-source discussion platform. Versions prior to 3.5.0.beta6 are vulnerable to cross-site scripting when the content security policy isn't enabled when using social logins. Version 3.5.0.beta6 patches the issue. As a workaround, have the content security policy enabled.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.007 (52.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.9% 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-2025-48954: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.001

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-48954?
CVE-2025-48954 is a high-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 8.1/10. Published 2025-06-25.
How severe is CVE-2025-48954?
High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2025-48954 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.