What is CVE-2025-71278?

CVE-2025-71278 is a high-severity vulnerability in Xenforo, classified under Incorrect Authorization. CVSS score: 8.8/10. Published 2026-04-01.

How severe is CVE-2025-71278?

High severity. CVSS v3 base score is 8.8 out of 10.

Auth bypass in Xenforo

CVE-2025-71278

XenForo before 2.3.5 allows OAuth2 client applications to request unauthorized scopes. This affects any customer using OAuth2 clients on any version of XenForo 2.3 prior to 2.3.5, potentially allowing client applications to gain access bey…

Vulnerability class: Broken Access Control

EPSS: 0.001 (16.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Xenforo — versions 2.3.0

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

XenForo 2.3.5 (Includes Security Fix) & Add-ons Released (vendor-advisory, patch)
VulnCheck Advisory: XenForo OAuth2 Unauthorized Scope Request (third-party-advisory)

Frequently asked questions

What is CVE-2025-71278?: CVE-2025-71278 is a high-severity vulnerability in Xenforo, classified under Incorrect Authorization. CVSS score: 8.8/10. Published 2026-04-01.
How severe is CVE-2025-71278?: High severity. CVSS v3 base score is 8.8 out of 10.