CVE-2014-4156Network attack vector

Unauthenticated user enumeration via AccessControl.pm

Published Jan 27, 2020 · Updated Aug 6, 2024

User enumeration in Proxmox VE before 3.2 allows remote attackers to identify valid account names via AccessControl.pm responses. AccessControl.pm returns distinguishable responses when queried with existing versus nonexistent users, exposing account validity through an unauthenticated network interface. No login or user interaction is required; impact is limited to disclosure of valid usernames and does not grant configuration or service control.

CVSS severity5.3
Medium
EPSS probability1.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

User enumeration in Proxmox VE before 3.2 allows remote attackers to identify valid account names via AccessControl.pm responses. AccessControl.pm returns distinguishable responses when queried with existing versus nonexistent users, exposing account validity through an unauthenticated network interface. No login or user interaction is required; impact is limited to disclosure of valid usernames and does not grant configuration or service control.

The record

CVE
CVE-2014-4156
Published
Jan 27, 2020
Updated
Aug 6, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy
T1087Account Discovery

Public exploit references

No public exploit references are available in this record.

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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