CVE-2023-54391

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-02. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
75(Track)
EG Risk 75/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
77%
KEV
Not listed

Published

September 1, 2026

Last Modified

September 8, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

Proxmox VE 7.0-8.0 Authentication Bypass via tfa-challenge Parameter | Advisories | VulnCheck

https://www.vulncheck.com/advisories/proxmox-ve-authentication-bypass-via-tfa-challenge-parameter
generic

git.proxmox.com Git - pve-access-control.git/commit

https://git.proxmox.com/?p=pve-access-control.git;a=commit;h=0f3d14d6be4d9f23e511701696a529ef3b7ffd61
generic

git.proxmox.com Git - pve-access-control.git/commit

https://git.proxmox.com/?p=pve-access-control.git;a=commit;h=032e7d6d441f89a48cadfd7f47e957c8a561c022
generic🔴 Active Exploitation

Proxmox Virtual Environment - Security Advisories | Page 4 | Proxmox Support Forum

https://forum.proxmox.com/threads/proxmox-virtual-environment-security-advisories.149331/page-4#post-867929

Vendor Advisories for CVE-2023-54391(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 58× in last 7d / 155× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 155 total refreshes for this CVE.

  1. 2026-09-19 05:33 UTCGHSA enrichment
  2. 2026-09-19 01:54 UTCGHSA enrichment
  3. 2026-09-18 22:15 UTCEG score recompute
  4. 2026-09-18 22:15 UTCGHSA enrichment
  5. 2026-09-18 19:26 UTCEPSS rescore
  6. 2026-09-18 18:37 UTCGHSA enrichment
  7. 2026-09-18 14:50 UTCGHSA enrichment
  8. 2026-09-18 11:12 UTCGHSA enrichment
  9. 2026-09-18 07:34 UTCGHSA enrichment
  10. 2026-09-18 03:56 UTCGHSA enrichment
  11. 2026-09-18 00:18 UTCGHSA enrichment
  12. 2026-09-17 20:40 UTCEG score recompute
  13. 2026-09-17 20:40 UTCGHSA enrichment
  14. 2026-09-17 13:17 UTCGHSA enrichment
  15. 2026-09-17 09:39 UTCGHSA enrichment
  16. 2026-09-17 06:00 UTCGHSA enrichment
  17. 2026-09-17 02:12 UTCGHSA enrichment
  18. 2026-09-16 22:33 UTCGHSA enrichment
  19. 2026-09-16 18:38 UTCEG score recompute
  20. 2026-09-16 18:38 UTCGHSA enrichment
  21. 2026-09-16 14:06 UTCEPSS rescore
  22. 2026-09-16 12:43 UTCGHSA enrichment
  23. 2026-09-16 09:05 UTCGHSA enrichment
  24. 2026-09-16 05:16 UTCEG score recompute
  25. 2026-09-16 05:16 UTCGHSA enrichment
Show 75 more
  1. 2026-09-16 05:11 UTCEPSS rescore
  2. 2026-09-16 05:11 UTCEPSS rescore
  3. 2026-09-16 01:38 UTCGHSA enrichment
  4. 2026-09-15 21:59 UTCGHSA enrichment
  5. 2026-09-15 18:21 UTCGHSA enrichment
  6. 2026-09-15 14:40 UTCGHSA enrichment
  7. 2026-09-15 11:01 UTCGHSA enrichment
  8. 2026-09-15 07:23 UTCGHSA enrichment
  9. 2026-09-15 03:44 UTCEG score recompute
  10. 2026-09-15 03:44 UTCGHSA enrichment
  11. 2026-09-15 03:08 UTCEPSS rescore
  12. 2026-09-15 00:06 UTCGHSA enrichment
  13. 2026-09-14 20:28 UTCGHSA enrichment
  14. 2026-09-14 16:43 UTCGHSA enrichment
  15. 2026-09-14 13:05 UTCGHSA enrichment
  16. 2026-09-14 09:27 UTCGHSA enrichment
  17. 2026-09-14 05:49 UTCGHSA enrichment
  18. 2026-09-14 02:11 UTCGHSA enrichment
  19. 2026-09-13 22:33 UTCGHSA enrichment
  20. 2026-09-13 18:55 UTCEG score recompute
  21. 2026-09-13 18:55 UTCGHSA enrichment
  22. 2026-09-13 16:45 UTCEPSS rescore
  23. 2026-09-13 15:17 UTCGHSA enrichment
  24. 2026-09-13 11:39 UTCGHSA enrichment
  25. 2026-09-13 08:00 UTCGHSA enrichment
  26. 2026-09-13 04:23 UTCGHSA enrichment
  27. 2026-09-13 00:45 UTCGHSA enrichment
  28. 2026-09-12 21:07 UTCGHSA enrichment
  29. 2026-09-12 17:29 UTCEG score recompute
  30. 2026-09-12 17:29 UTCGHSA enrichment
  31. 2026-09-12 14:58 UTCEPSS rescore
  32. 2026-09-12 13:51 UTCGHSA enrichment
  33. 2026-09-12 10:13 UTCGHSA enrichment
  34. 2026-09-12 06:34 UTCGHSA enrichment
  35. 2026-09-12 02:55 UTCGHSA enrichment
  36. 2026-09-11 23:17 UTCGHSA enrichment
  37. 2026-09-11 19:11 UTCGHSA enrichment
  38. 2026-09-11 15:33 UTCEG score recompute
  39. 2026-09-11 15:33 UTCGHSA enrichment
  40. 2026-09-11 14:51 UTCEPSS rescore
  41. 2026-09-11 11:55 UTCEG score recompute
  42. 2026-09-11 11:55 UTCGHSA enrichment
  43. 2026-09-11 09:34 UTCEPSS rescore
  44. 2026-09-11 08:17 UTCGHSA enrichment
  45. 2026-09-11 04:39 UTCGHSA enrichment
  46. 2026-09-11 01:01 UTCGHSA enrichment
  47. 2026-09-10 21:23 UTCGHSA enrichment
  48. 2026-09-10 17:45 UTCGHSA enrichment
  49. 2026-09-10 14:07 UTCGHSA enrichment
  50. 2026-09-10 10:30 UTCEG score recompute
  51. 2026-09-10 10:30 UTCGHSA enrichment
  52. 2026-09-10 06:51 UTCGHSA enrichment
  53. 2026-09-10 03:13 UTCGHSA enrichment
  54. 2026-09-09 23:35 UTCGHSA enrichment
  55. 2026-09-09 18:45 UTCGHSA enrichment
  56. 2026-09-09 15:07 UTCGHSA enrichment
  57. 2026-09-09 11:29 UTCGHSA enrichment
  58. 2026-09-09 07:51 UTCGHSA enrichment
  59. 2026-09-09 04:13 UTCGHSA enrichment
  60. 2026-09-09 00:29 UTCEG score recompute
  61. 2026-09-09 00:28 UTCGHSA enrichment
  62. 2026-09-08 21:58 UTCEPSS rescore
  63. 2026-09-08 20:50 UTCGHSA enrichment
  64. 2026-09-08 10:01 UTCGHSA enrichment
  65. 2026-09-08 05:27 UTCGHSA enrichment
  66. 2026-09-08 01:47 UTCGHSA enrichment
  67. 2026-09-07 22:09 UTCGHSA enrichment
  68. 2026-09-07 18:31 UTCEG score recompute
  69. 2026-09-07 18:31 UTCGHSA enrichment
  70. 2026-09-07 15:59 UTCEPSS rescore
  71. 2026-09-07 14:53 UTCGHSA enrichment
  72. 2026-09-07 10:53 UTCGHSA enrichment
  73. 2026-09-07 07:14 UTCGHSA enrichment
  74. 2026-09-07 03:35 UTCGHSA enrichment
  75. 2026-09-06 23:52 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2023/CVE-2023-54391.yaml
    First seen Jan 1, 2023

    Proxmox VE - Default Credentials with TFA Bypass

    Open source ↗

Frequently asked(5)

What is CVE-2023-54391?
CVE-2023-54391 is a critical vulnerability published on September 1, 2026. 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…
When was CVE-2023-54391 disclosed?
CVE-2023-54391 was first published in the National Vulnerability Database on September 1, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-54391 actively exploited?
CVE-2023-54391 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 23.2% of all scored CVEs.
What is the CVSS score of CVE-2023-54391?
CVE-2023-54391 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2023-54391?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-54391, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2023-54391

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