CVE-2025-41239VulnerabilityPublished 15 Jul 2025

CVE-2025-41239: VMware ESXi · Use of Uninitialized Resource

Affects VMware ESXiSource CVE Database V5

Not known to be exploited · CVSS 7.1 High.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

7.1High

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

EPSS: 3.1% chance of exploitation in 30 days – higher than 87% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 15 Jul 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 26 Oct 2026.

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

Affected software

Product	Affected	Fixed in
Vmwarevmware/esxi`pkg:rpm/vmware/esxi`Other threats	Affected =7.0 =8.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2025-41239, European organizations should implement the following specific measures: 1) Restrict and monitor administrative access to virtual machines rigorously to prevent unauthorized local admin privileges that could be leveraged for exploitation. 2) Apply the latest VMware security advisories and patches as soon as they become available, prioritizing ESXi hosts and management tools. 3) Employ strict network segmentation and isolation policies between virtual machines to limit the impact of any potential memory disclosure. 4) Use runtime security monitoring tools capable of detecting anomalous inter-VM communication or unusual vSocket usage patterns. 5) Conduct regular audits of VM configurations and privilege assignments to minimize the attack surface. 6) For cloud providers, enforce tenant isolation policies and consider additional encryption or memory protection mechanisms at the hypervisor level. 7) Educate administrators and security teams about the risks of uninitialized memory vulnerabilities and the importance of patch management. These steps go beyond generic advice by focusing on access control, monitoring, and isolation specific to the VMware virtualization context.

Description

VMware ESXi, Workstation, Fusion, and VMware Tools contains an information disclosure vulnerability due to the usage of an uninitialised memory in vSockets. A malicious actor with local administrative privileges on a virtual machine may be able to exploit this issue to leak memory from processes communicating with vSockets.

Impact

For European organizations, the impact of CVE-2025-41239 can be substantial. Many enterprises, cloud service providers, and data centers across Europe rely heavily on VMware ESXi for virtualization infrastructure. Exploitation could lead to unauthorized disclosure of sensitive data across virtual machines, undermining data confidentiality and potentially violating data protection regulations such as GDPR. This is particularly critical for sectors handling sensitive personal data, financial information, or intellectual property. The vulnerability requires local administrative access on a VM, which means that initial compromise or insider threats could escalate to cross-VM data leakage. This could facilitate lateral movement within virtualized environments, increasing the attack surface. The lack of integrity or availability impact limits the scope to confidentiality breaches, but the potential exposure of sensitive memory contents can have cascading effects on organizational security posture and compliance. Additionally, cloud providers operating VMware-based infrastructure in Europe could face reputational damage and regulatory scrutiny if customer data is exposed due to this vulnerability.

CWE-908Use of Uninitialized Resource (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product uses or accesses a resource that has not been initialized.
Implementation
Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.
Implementation
Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.
Implementation
Avoid race conditions (CWE-362) during initialization routines.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/35877 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2025, 19:01 UTC

WeaknessesCWE-908

Technical details

References

Community reviews

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