CVE-2023-54391
Proxmox VE 7.0-8.0 Authentication Bypass via tfa-challenge Parameter
- State
- Published
- Severity
- 9.3 Critical
- Published
- Sep 1, 2026
- Updated
- Oct 1, 2026
- Reserved
- Sep 1, 2026
Description
Proxmox Virtual Environment (VE) 7.0 through 8.0 contains an authentication bypass vulnerability in libpve-access-control before 8.0.4 that allows unauthenticated attackers to authenticate as any existing enabled user without a configured second factor by supplying an arbitrary tfa-challenge value in the API login endpoint. Attackers can send a POST request to the access ticket API endpoint with any value in the tfa-challenge parameter to completely skip password verification, gaining unauthorized access including to the root@pam account. All affected releases are end of life.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-304 Missing Critical Step in Authentication
Affected Products
| Product | Versions |
|---|---|
Proxmox Virtual Environment (VE)Proxmox Server Solutions GmbH |
|
References
- Vendor Advisoryvendor-advisory
- Patch Commitpatch
- Introducing Commit
- https://www.vulncheck.com/advisories/proxmox-ve-authentication-bypass-via-tfa-challenge-parameterthird-party-advisory
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