Vulnerability details
CVE-2026-63438
2FAuth: Reverse Proxy Guard Auto-Creates Users With Admin Promotion From Unauthenticated Header Value
Official description
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 accepts authentication headers from a client that did not pass through a trusted proxy, RemoteUserProvider::retrieveById() creates an account for an unknown REMOTE_USER, promotes the first created account to administrator, and synchronizes the account email from the configured mail header. An unauthenticated remote client can therefore create an administrator on a fresh instance or impersonate and redirect email for a known account, exposing 2FA secrets and administrative functions. This issue is fixed in version 8.0.0.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.8Critical | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Bubka | 2FAuth | < 8.0.0 | CVEProject cvelistV5 (CNA) |
References and advisories
5- https://github.com/Bubka/2FAuth/commit/43873cbfba445926c7008b4291eeee67752af9e8 x_refsource_MISC
- https://github.com/Bubka/2FAuth/commit/8a4c395cac97f8b70b4a822639a6ad8a816f927c x_refsource_MISC
- https://github.com/Bubka/2FAuth/commit/d9e58ac4a63fbd8a073e423567881c81a87915de x_refsource_MISC
- https://github.com/Bubka/2FAuth/releases/tag/v8.0.0 x_refsource_MISC
- https://github.com/Bubka/2FAuth/security/advisories/GHSA-r9xx-45m8-mw24 x_refsource_CONFIRM
Details
- Published
- 2026-11-06
- Last updated
- 2026-11-10
- State
- Published
- Assigner (CNA)
- GitHub_M
- Kolun priority
- 26 · Low
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-287Improper Authentication