CVE-2025-48954 | 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.

Published: 2025-06-25 Last update: 2025-09-25 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-48954 is rated Moderate Risk (64.3/100): CVSS High severity, with high exploitation likelihood (EPSS 10.12%, 93th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-48954

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-23 10.78% 10.12% -0.65%
2 2026-04-21 13.96% 10.78% -3.19%
3 2026-03-11 — 13.96% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-48954

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 5.2 [email protected]
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2025-48954

Affected software / configurations for CVE-2025-48954

Vendor Product Version Raw CPE
discourse discourse < 3.5.0 cpe:2.3:a:discourse:discourse:*:*:*:*:beta:*:*:*
discourse discourse 3.5.0 cpe:2.3:a:discourse:discourse:3.5.0:beta1:*:*:beta:*:*:*
discourse discourse 3.5.0 cpe:2.3:a:discourse:discourse:3.5.0:beta2:*:*:beta:*:*:*
discourse discourse 3.5.0 cpe:2.3:a:discourse:discourse:3.5.0:beta3:*:*:beta:*:*:*
discourse discourse 3.5.0 cpe:2.3:a:discourse:discourse:3.5.0:beta4:*:*:beta:*:*:*
discourse discourse 3.5.0 cpe:2.3:a:discourse:discourse:3.5.0:beta5:*:*:beta:*:*:*

References for CVE-2025-48954

cvelogic Threat Intelligence