CVE-2023-54391 json
Proxmox VE 7.0-8.0 Authentication Bypass via tfa-challenge Parameter
published 2026-09-01 2 mo ago modified 2026-10-01 39 d ago also EUVD-2023-60613
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 3.0%
- EPSS 3.0% chance of exploitation in 30 days, percentile 87%
- public exploits
- 0
- none known, plus a Nuclei check
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 2 mo ago
Exploit prediction
3.02% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- Nuclei template Proxmox VE - Default Credentials with TFA Bypass nuclei detection template
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | 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 |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 9.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- Proxmox Server Solutions GmbH Proxmox Virtual Environment (VE)
Classification
- Weakness
-
- CWE-304 Missing Critical Step in Authentication
References
-
git.proxmox.com
/?p=pve-access-control.git;a=commit;h=032e7d6d441f89a48cadfd7f47e957c8a561c022
patch
- git.proxmox.com /?p=pve-access-control.git;a=commit;h=0f3d14d6be4d9f23e511701696a529ef3b7ffd61
-
forum.proxmox.com
/threads/proxmox-virtual-environment-security-advisories.149331/page-4#post-867929
vendor-advisory
-
vulncheck.com
/advisories/proxmox-ve-authentication-bypass-via-tfa-challenge-parameter
third-party-advisory
Sources
- CVE List CVE-2023-54391
- NVD CVE-2023-54391
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