CVE-2025-41252VulnerabilityPublished 29 Sep 2025

CVE-2025-41252: VMware NSX · Observable Discrepancy

Affects VMware NSXSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in 4.6.0 : patch VMware NSX soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.6.0, 4.3.0, 4.2.0 +1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade VMware NSX to 4.6.0, 4.3.0, 4.2.0 or 4.1.0.

Affected software

Product	Affected	Fixed in
VMware NSX	Affected >=4.2.0 <4.3.0 >=4.1.0 <4.2.0 >=4.0.0 <4.1.0 >=4.5.0 <4.6.0	Fixed in 4.3.0 4.2.0 4.1.0 4.6.0

AI-suggested

European organizations should prioritize immediate patching of affected VMware NSX and NSX-T deployments to the fixed versions specified by VMware (e.g., NSX 9.0.1.0, 4.2.2.2/4.2.3.1, 4.1.2.7, NSX-T 3.2.4.3). Since no workarounds exist, patch management is critical. Additionally, organizations should: 1) Restrict access to NSX management interfaces using network segmentation and firewall rules to limit exposure only to trusted administrative networks; 2) Implement strong multi-factor authentication (MFA) on all NSX user accounts to mitigate the risk of credential-based attacks following username enumeration; 3) Monitor authentication logs and network traffic for unusual login attempts or enumeration activity; 4) Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect enumeration patterns; 5) Conduct regular security audits and penetration testing focusing on NSX components; 6) Educate administrators on recognizing and responding to suspicious activity related to NSX management access. These measures, combined with patching, will reduce the attack surface and improve detection and response capabilities.

Description

Description: VMware NSX contains a username enumeration vulnerability. An unauthenticated malicious actor may exploit this to enumerate valid usernames, potentially leading to unauthorized access attempts. Impact: Username enumeration → facilitates unauthorized access. Attack Vector: Remote, unauthenticated. Severity: Important. CVSSv3: 7.5 (High). Acknowledgments: Reported by the National Security Agency. Affected Products: * VMware NSX 9.x.x.x, 4.2.x, 4.1.x, 4.0.x * NSX-T 3.x * VMware Cloud Foundation (with NSX) 5.x, 4.5.x Fixed Versions: * NSX 9.0.1.0; 4.2.2.2/4.2.3.1 http://4.2.2.2/4.2.3.1 ; 4.1.2.7; NSX-T 3.2.4.3; CCF async patch (KB88287). Workarounds: None.

Impact

For European organizations, the impact of CVE-2025-41252 is significant due to the widespread adoption of VMware NSX for network virtualization and micro-segmentation in enterprise data centers and cloud environments. Username enumeration facilitates attackers in identifying valid user accounts, which can be used to launch targeted brute force or credential stuffing attacks, potentially compromising administrative accounts that control critical network infrastructure. Unauthorized access to NSX management components could lead to lateral movement within networks, data exfiltration, or disruption of network segmentation policies, undermining security postures. Given the reliance on NSX in sectors such as finance, healthcare, telecommunications, and government within Europe, exploitation could have cascading effects on confidentiality and operational security. The remote and unauthenticated nature of the vulnerability increases the risk profile, especially for organizations exposing NSX management interfaces to less trusted networks or the internet. Although no direct integrity or availability impacts are noted, the confidentiality breach alone can facilitate more severe attacks.

CWE-203Observable Discrepancy (opens in a new tab)
Base weakness
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended).
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Black Box Reverse Engineering (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

https//support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/36150 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Sep 2025, 19:05 UTC

WeaknessesCWE-203

Technical details

References

Community reviews

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