Vulnerability in Proxmox Server Solutions Gmbh Virtual Environment (Ve)
CVE-2023-54391
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.031 (87.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 87.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.017 · newest: 0.031 · change: +0.013
Affected products
- Proxmox Server Solutions Gmbh Virtual Environment (Ve) — versions 8.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- Vendor Advisory (vendor-advisory)
- Patch Commit (patch)
- www.vulncheck.com/advisories/proxmox-ve-authentication-bypass-via-tfa-challenge… (third-party-advisory)
- Introducing Commit
Frequently asked questions
- What is CVE-2023-54391?
- CVE-2023-54391 is a critical-severity vulnerability in Proxmox Server Solutions Gmbh Virtual Environment (Ve), classified under Missing Critical Step in Authentication. CVSS score: 9.8/10. Published 2026-09-01.
- How severe is CVE-2023-54391?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2023-54391 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.