CVE-2021-21974

Name: CVE-2021-21974
Creator: NVD / NIST
Published: 2021-02-24T17:15:16.017+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 45.06%

Last modified Jun 17, 2026

CVE-2021-21974 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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.. EPSS estimates a 45.06% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

45.06%

98.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Vmware	Cloud Foundation	>= 3.0, < 3.10.1.2
Vmware	Cloud Foundation	>= 4.0, < 4.2
Vmware	Esxi	6.5
Vmware	Esxi	6.7
Vmware	Esxi	7.0.0

References

http://packetstormsecurity.com/files/162957/VMware-ESXi-OpenSLP-Heap-Overflow.htmlExploit, Third Party Advisory, VDB Entry
https://www.vmware.com/security/advisories/VMSA-2021-0002.htmlVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-250/Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/162957/VMware-ESXi-OpenSLP-Heap-Overflow.htmlExploit, Third Party Advisory, VDB Entry
https://www.vmware.com/security/advisories/VMSA-2021-0002.htmlVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-250/Third Party Advisory, VDB Entry

Timeline

Published: Feb 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21974?

How severe is CVE-2021-21974?

CVE-2021-21974 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 45.06% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21974?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21974?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST