OAuth Implementation Vulnerability in phpBB by phpBB Group
CVE-2026-48612

8HIGH

Key Information:

Vendor

PHPbb

Status
PHPbb
Vendor
CVE Published:
12 June 2026

What is CVE-2026-48612?

An improper state verification vulnerability in the OAuth implementation of phpBB can be exploited by malicious actors to manipulate the authentication flow. This allows an attacker to link a victim’s account with their own, leading to unauthorized account linking and significantly increasing the risk of account takeover. It is crucial for users of phpBB to ensure their installations are updated to mitigate these risks.

Affected Version(s)

phpBB 3.3.0 <= 3.3.16

References

https://www.phpbb.com/community/viewtopic.php?t=2672170

CVSS V3.0

Score:
8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.