CONFERENCE CISO Forum Virtual Summit 2026 - View all Sessions
Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Vulnerabilities

Patch for Critical VMware ESXi Vulnerability Incomplete

VMware on Wednesday informed customers that it has released new patches for ESXi after learning that a fix made available last month for a critical vulnerability was incomplete.

VMware on Wednesday informed customers that it has released new patches for ESXi after learning that a fix made available last month for a critical vulnerability was incomplete.

The vulnerability, tracked as CVE-2020-3992, was described as a use-after-free bug that affects the OpenSLP service in ESXi. A remote, unauthenticated attacker can exploit the flaw to execute arbitrary code.

However, VMware said the attacker needs to be on the management network and have access to port 427 on an ESXi machine in order to exploit the flaw.

VMware learned about the security hole in July from Lucas Leong of Trend Micro’s Zero Day Initiative (ZDI). An advisory was also published in October by ZDI.

“The specific flaw exists within the processing of SLP messages. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the SLP daemon,” ZDI said.

VMware updated its initial advisory on Wednesday to inform customers that the patches had been incomplete. New fixes have now been released for ESXi 6.5, 6.7 and 7.0, but patches are still pending for VMware Cloud Foundation, the hybrid cloud platform for managing virtual machines and orchestrating containers.

Advertisement. Scroll to continue reading.

VMware failing to patch a vulnerability on the first try is not unheard of. Earlier this year, the company made several attempts to patch a privilege escalation flaw affecting the macOS version of Fusion.

Related: Google Researcher Finds Vulnerability in VMware Virtualization Products

Related: VMware Cloud Director Vulnerability Has Major Impact for Cloud Providers

Related: VMware Again Fails to Patch Privilege Escalation Vulnerability in Fusion

Written By

Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing for the latest cybersecurity threats, trends, and expert insights.

Click to comment

You must be logged in to post a comment Login

Leave a Reply

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

NOW LIVE: CISO Forum 2026 Summit

Join as we bring together CISOs, senior cybersecurity executives, practitioners, industry experts, and other security leaders to share practical experience and examine the issues shaping enterprise cybersecurity strategy.

Register

Join to learn the four levels of architecting security into the agentic SDLC – from securing the code your developers' agents write to running a coordinated system of security agents you've built yourself.

Register

People on the Move

Cohere has appointed Jaya Baloo as CISO.

Jensen Huang has resigned as President and Chief Executive Officer at NVIDIA.

Sean Sweeney has become CIO of the City of Charleston, South Carolina.

More People On The Move

Expert Insights

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest cybersecurity news, threats, and expert insights. Unsubscribe at any time.