What’s Vulnerable › Vulnerabilities

CVE-2026-73313: XenForo < 2.3.13 MFA Bypass via Passkey TFA Provider

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-08 · updated 2026-09-14
• Weakness: CWE-863

Description

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 products

• XenForo: before 2.3.13 — fixed in 2.3.13

How to fix

Upgrade to a fixed version: XenForo 2.3.13. Check the vendor advisory for mitigations.

References

• https://bombobombone.github.io/posts/cve-2026-73313/
• https://github.com/BomboBombone/CVE-2026-73313
• https://www.vulncheck.com/advisories/xenforo-mfa-bypass-via-passkey-tfa-provider
• https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/
• https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/

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