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21Track

2FAuth: Reverse Proxy Guard Trusts Client-Supplied Headers Without Proxy Verification

Bubka 2FAuth · CVE-2026-63439 ETK-2026-3759 EUVD-2026-118492 GHSA-MH8R-74X2-R457
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Assessment: Track

SSVC decision points: exploitation none, automatable yes, technical impact total, deployment low.

What is it?

2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, when AUTHENTICATION_GUARD=reverse-proxy-guard is enabled, ReverseProxyGuard::user() reads the default REMOTE_USER identity header, or a custom identity header selected by the AUTH_PROXY_HEADER_FOR_USER configuration setting, without confirming that the request originated from a configured trusted proxy. A remote client that can reach the application directly can forge the selected identity header and authenticate as an existing user, including an administrator, gaining access to stored 2FA secrets and account or application management functions. This issue is fixed in version 8.0.0.

Evidence

No coverage recorded yet.

Exploitation

  • Exploit code published (not verified by us)
  • Exploited in the wild (confirmed by a source)
  • Listed as known exploited (CISA KEV)
CVSS
9.8
EPSS
0.4%
First seen
1 d ago
Status
corroborated

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