CVE-2023-54391

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

3.02% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 87.3% of scored records. A rank, not a probability.

NVD base score

9.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Deferred. NVD last modified this record on 2026-09-08.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-01 21:59Z1 MO AGO

Last updated

2026-10-01 15:19Z28 DAYS AGO

Reserved

2026-09-01

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Critical (CVSS 9.3)

CNA CVSS vector

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

Weaknesses

• CWE-304Missing Critical Step in AuthenticationBase

Data version

5.2

Document digest

6cc765937091d7ea2efd0d9a20cfe7385bdf1d5d199eb7cbf4eddacd45771511

• forum.proxmox.comVendor Advisoryhttps://forum.proxmox.com/threads/proxmox-virtual-environment-security-advisories.149331/page-4#post-867929vendor-advisory
• git.proxmox.comPatch Commithttps://git.proxmox.com/?p=pve-access-control.git;a=commit;h=032e7d6d441f89a48cadfd7f47e957c8a561c022patch
• git.proxmox.comIntroducing Commithttps://git.proxmox.com/?p=pve-access-control.git;a=commit;h=0f3d14d6be4d9f23e511701696a529ef3b7ffd61
• www.vulncheck.comhttps://www.vulncheck.com/advisories/proxmox-ve-authentication-bypass-via-tfa-challenge-parameterthird-party-advisory