VMware has urged customers to immediately patch a critical vulnerability affecting vCenter Server, the management interface for vSphere environments.
The vulnerability, tracked as CVE-2021-21985, was reported to VMware by Ricter Z of 360 Noah Lab and it has been patched in versions 6.5, 6.7 and 7.0 of vCenter Server.
According to VMware, the vulnerability impacts the vSphere Client, specifically the Virtual SAN Health Check plugin, which is enabled by default in vCenter Server even if the plugin is not actually being used. An attacker with access to port 443 can exploit the flaw to execute commands with elevated privileges on the operating system that hosts vCenter Server.
Another vulnerability patched by the same updates, tracked as CVE-2021-21986 and rated medium severity, is related to an authentication mechanism for the Virtual SAN Health Check, Site Recovery, vSphere Lifecycle Manager, and VMware Cloud Director Availability plugins. An unauthenticated attacker with access to port 443 can leverage the weakness to perform actions allowed by the affected plugins.
VMware has published an advisory, a blog post, and an FAQ document for these vulnerabilities, and urged customers to take action immediately, warning that “the ramifications of this vulnerability are serious.”
“In this era of ransomware it is safest to assume that an attacker is already inside the network somewhere, on a desktop and perhaps even in control of a user account, which is why we strongly recommend declaring an emergency change and patching as soon as possible,” the company warned.
Installing the available patches is ideal, but there are also some workarounds and mitigations that can help prevent attacks. In addition to the patches, VMware has made some improvements to plugin authentication in the vCenter Server plugin framework.
Hackers targeting vCenter Server flaws is not unheard of. In the case of a vulnerability disclosed in February, scanning for affected systems started only one day after the availability of patches was announced by VMware.
Related: VMware Patches Critical Flaw Reported by Sanctioned Russian Security Firm
Related: VMware Patches Remote Code Execution Vulnerability in View Planner
Related: VMware Patches Critical Flaw in Carbon Black Cloud Workload

Eduard Kovacs (@EduardKovacs) is a managing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.
More from Eduard Kovacs
- China’s Offensive Cyber Operations in Africa Support Soft Power Efforts
- SANS Survey Shows Drop in 2023 ICS/OT Security Budgets
- Apple Patches 3 Zero-Days Likely Exploited by Spyware Vendor to Hack iPhones
- Cisco to Acquire Splunk for $28 Billion
- Car Cybersecurity Study Shows Drop in Critical Vulnerabilities Over Past Decade
- Omron Patches PLC, Engineering Software Flaws Discovered During ICS Malware Analysis
- Intel Launches New Attestation Service as Part of Trust Authority Portfolio
- Atos Unify Vulnerabilities Could Allow Hackers to Backdoor Systems
Latest News
- Researchers Discover Attempt to Infect Leading Egyptian Opposition Politician With Predator Spyware
- In Other News: New Analysis of Snowden Files, Yubico Goes Public, Election Hacking
- China’s Offensive Cyber Operations in Africa Support Soft Power Efforts
- Air Canada Says Employee Information Accessed in Cyberattack
- BIND Updates Patch Two High-Severity DoS Vulnerabilities
- Faster Patching Pace Validates CISA’s KEV Catalog Initiative
- SANS Survey Shows Drop in 2023 ICS/OT Security Budgets
- Apple Patches 3 Zero-Days Likely Exploited by Spyware Vendor to Hack iPhones
