CVE-2026-73313: XenForo < 2.3.13 MFA Bypass via Passkey TFA Provider
XenForo before 2.3.13 contains a multi-factor authentication bypass vulnerability in the passkey TFA provider that allows an authenticated attacker to complete login as another user by submitting their own registered passkey credential during the WebAuthn assertion step. The passkey verification path performs a global credential lookup without validating that the matched credential belongs to the user whose login is pending, enabling an attacker who knows a target account's password to sign the challenge with their own passkey and bypass multi-factor authentication on both public forum and ACP login paths.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
XenForoto a version that resolves this vulnerability.Fixed in 2.3.13
Event History
Frequently Asked Questions
What does an attacker need to exploit this issue?
The attacker must be authenticated and have a passkey credential registered to their own account. They also need to know the target account's password so they can reach the target's pending WebAuthn assertion step and submit their own passkey credential.
Which login surfaces are affected?
The bypass affects both public forum login and Admin Control Panel (ACP) login paths when the passkey TFA provider is used.
Which deployments should be prioritized for remediation?
XenForo installations earlier than 2.3.13 should be prioritized, particularly where passkey-based two-factor authentication is enabled and accounts with sensitive permissions use it. The issue can affect administrative accounts through the ACP login path.