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CVE-2023-54391

Proxmox VE 7.0-8.0 Authentication Bypass via tfa-challenge Parameter

Published: Sep 1, 2026Updated: Sep 3, 2026 Sources: CVE List NVDCWE-304
9.8CRITICAL
NVD MITRE
EPSS Score
1.7%
Top 23.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Nuclei

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-304

Affected Products

Proxmox Server Solutions GmbH
commercial·DEaka proxmox mail gateway, proxmox ve
Proxmox Virtual Environment (VE)On-prem
Cloud & SaaS / virtualization

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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References

https://forum.proxmox.com/threads/proxmox-virtual-environment-security-advisories.149331/page-4#post-867929
forum.proxmox.com
https://git.proxmox.com/?p=pve-access-control.git;a=commit;h=032e7d6d441f89a48cadfd7f47e957c8a561c022
git.proxmox.com
https://git.proxmox.com/?p=pve-access-control.git;a=commit;h=0f3d14d6be4d9f23e511701696a529ef3b7ffd61
git.proxmox.com
and 1 more references View all →

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