CVE-2025-71278 PUBLISHED

XenForo OAuth2 Unauthorized Scope Request

Assigner: VulnCheck
Reserved: 01.04.2026 Published: 01.04.2026 Updated: 01.04.2026

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 beyond their intended authorization level.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 8.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	XenForo
Product	XenForo
Versions	affected from 2.3.0 to 2.3.5 (excl.)

References

Problem Types

Incorrect Authorization CWE