CVE-2021-21974

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 45.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-02-24 · updated 2026-06-17
Weakness: CWE-787

Description

OpenSLP as used in ESXi (7.0 before ESXi70U1c-17325551, 6.7 before ESXi670-202102401-SG, 6.5 before ESXi650-202102101-SG) has a heap-overflow vulnerability. A malicious actor residing within the same network segment as ESXi who has access to port 427 may be able to trigger the heap-overflow issue in OpenSLP service resulting in remote code execution.

Affected products

VMware Cloud Foundation: from 3.0 before 3.10.1.2; from 4.0 before 4.2 — fixed in 3.10.1.2, 4.2
VMware ESXi: 6.5-2, 6.5-650-201701001, 6.5-650-201703001, 6.5-650-201703002, 6.5-650-201704001, 6.5-650-201707101 (+222); 6.5, 6.7, 7.0.0
VMware Cloud Foundation: 4.x before 4.2 and 3.x
VMware ESXi: 7.0 before ESXi70U1c-17325551, 6.7 before ESXi670-202102401-SG, 6.5 before ESXi650-202102101-SG

How to fix

Upgrade to a fixed version: VMware Cloud Foundation 3.10.1.2, 4.2. Check the vendor advisory for mitigations.

References

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