CVE-2025-41252Network attack vector

Username enumeration via inconsistent login errors

Published Sep 29, 2025 · Updated Sep 29, 2025

Username enumeration in VMware NSX 3.x, 4.0.x through 4.2.x, and 9.x allows remote attackers to identify valid accounts. The NSX login page returns inconsistent error messages for valid and invalid usernames, creating an unauthenticated account-existence oracle. Network access to the NSX management interface is required; the disclosed account names facilitate password guessing and unauthorized access attempts.

CVSS severity7.5
High
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Username enumeration in VMware NSX 3.x, 4.0.x through 4.2.x, and 9.x allows remote attackers to identify valid accounts. The NSX login page returns inconsistent error messages for valid and invalid usernames, creating an unauthenticated account-existence oracle. Network access to the NSX management interface is required; the disclosed account names facilitate password guessing and unauthorized access attempts.

The record

CVE
CVE-2025-41252
Published
Sep 29, 2025
Updated
Sep 29, 2025
Vendor
VMware
Product
VMware NSX
Classifications
CWE-203, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 29, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=VMware Cloud Foundation (with NSX) 5.x, 4.5.x
  2. Affected versionversion=VMware NSX 9.x.x.x, 4.2.x, 4.1.x, 4.0.x
  3. Affected versionversion=VMware NSX-T 3.x

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

VMware · VMware NSXversion=VMware Cloud Foundation (with NSX) 5.x, 4.5.x; version=VMware NSX 9.x.x.x, 4.2.x, 4.1.x, 4.0.x; version=VMware NSX-T 3.x

Published CVSS scores

7.5VMwareCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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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