Paper/Archive/CVE-2026-63439

CVE-2026-63439

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

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
2FAuth< 8.0.0–CNA

Scores by source

GitHub_M (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

refgithub.com/Bubka/2FAuth/security/advisories/GHSA-mh8r-74x2-r457refgithub.com/Bubka/2FAuth/commit/43873cbfba445926c7008b4291eeee67752af9e8refgithub.com/Bubka/2FAuth/releases/tag/v8.0.0