CVE-2023-43320Public exploitNetwork attack vector

Privilege escalation via unrestricted TOTP guessing

Published Sep 27, 2023 · Updated Nov 26, 2024

TOTP bypass in affected Proxmox VE, Backup Server, and Mail Gateway releases allows remote authenticated users to escalate privileges. The TFA state does not limit consecutive TOTP guesses, enabling repeated attempts against the authentication-ticket flow. Attackers need valid primary credentials for a TOTP-protected account; guessing the second factor grants that account's privileges.

CVSS severity8.8
High
EPSS probability0.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOTP bypass in affected Proxmox VE, Backup Server, and Mail Gateway releases allows remote authenticated users to escalate privileges. The TFA state does not limit consecutive TOTP guesses, enabling repeated attempts against the authentication-ticket flow. Attackers need valid primary credentials for a TOTP-protected account; guessing the second factor grants that account's privileges.

The record

CVE
CVE-2023-43320
Published
Sep 27, 2023
Updated
Nov 26, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1110
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 26, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1110Brute Force

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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