Cyber Resilience

CVE-2021-21974

HighPublic PoCUpdated

Published: 24 February 2021

Published
24 February 2021
Modified
02 June 2026
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.5570 98.1th percentile
Risk Priority 51 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-21974 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Vmware Esxi. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 1.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

the heap-overflow issue in OpenSLP service resulting in remote code execution.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

vmware
cloud foundation
3.0 — 3.10.1.2 · 4.0 — 4.2
vmware
esxi
6.5, 6.7, 7.0.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References