Discourse XSS via Social Logins (pre-3.5.0.beta6, CSP off)
CVE-2025-48954 Published on June 25, 2025

Discourse vulnerable to XSS via user-provided query parameter in oauth failure flow
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.

NVD

Vulnerability Analysis

CVE-2025-48954 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
NONE

Weakness Type

What is a XSS Vulnerability?

The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

CVE-2025-48954 has been classified to as a XSS vulnerability or weakness.


Products Associated with CVE-2025-48954

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Affected Versions

discourse Version < 3.5.0.beta6 is affected by CVE-2025-48954

Exploit Probability

EPSS
15.58%
Percentile
94.58%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.