CVE-2023-54391 Proxmox VE 7.0-8.0 Authentication Bypass via tfa-challenge Parameter
Unauthenticated attackers can bypass authentication and gain root access by supplying an arbitrary tfa-challenge value in the API login endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-54391?
CVE-2023-54391 is a critical authentication bypass vulnerability in Proxmox Virtual Environment (VE), published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-304
Which versions are affected by CVE-2023-54391?
How do I fix CVE-2023-54391?
No fix has been published for CVE-2023-54391 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2023-54391 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-54391 exists.
Public exploit code: 1 Nuclei template and 3 proofs of concept on GitHub.
Sources
Also known as GHSA-m457-grcf-698x.