CVE-2025-48954Public exploitNetwork attack vector

Script execution via reflected OAuth provider parameter

Published Jun 25, 2025 · Updated Jun 25, 2025

Cross-site scripting in Discourse before 3.5.0.beta6 allows remote attackers to execute script via a crafted OAuth failure link. The /auth/failure handler reflects the provider query parameter into its HTML response without neutralizing script-capable markup. Exploitation requires social login, disabled CSP, and a user to follow the crafted link; injected code runs in the forum origin.

CVSS severity8.1
High
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Discourse before 3.5.0.beta6 allows remote attackers to execute script via a crafted OAuth failure link. The /auth/failure handler reflects the provider query parameter into its HTML response without neutralizing script-capable markup. Exploitation requires social login, disabled CSP, and a user to follow the crafted link; injected code runs in the forum origin.

The record

CVE
CVE-2025-48954
Published
Jun 25, 2025
Updated
Jun 25, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-80, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.5.0.beta6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=< 3.5.0.beta6

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
8.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1204.001Malicious Link

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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