CVE-2020-3992

VMware ESXi: OpenSLP Use-After-Free

As of , CVE-2020-3992 in VMware ESXi is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 3 November 2021
US federal deadline
3 May 2022181 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Known
EPSS score
0.83Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

VMware ESXi OpenSLP contains a use-after-free vulnerability that allows an attacker residing in the management network with access to port 427 to perform remote code execution.

CISA's description

OpenSLP as used in VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG) has a use-after-free issue. A malicious actor residing in the management network who has access to port 427 on an ESXi machine may be able to trigger a use-after-free in the OpenSLP service resulting in remote code execution.

The CVE record's description, from vmware

CVE published
20 October 2020
Assigned by
vmware
CVSS
9.8 Critical (CVSS 3.1, from CISA-ADP)
CWE-416
Use After Free
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

ESXi: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2024-37085Authentication BypassVMware ESXiPatch this weekRansomware use0.27
CVE-2025-22225Arbitrary WriteVMware ESXiPatch this weekRansomware use0.01

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