How severe is CVE-2021-22017?

CVE-2021-22017 has a CVSS 3.1 base score of 5.3 (MEDIUM). EPSS estimates a 49.2% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2021-22017: VMware vCenter Server Improper Access Control

CISA Known Exploited Vulnerabilities

VMware vCenter Server Improper Access Control is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2022-01-10

Remediation due

2022-01-24

Required action
Apply updates per vendor instructions.

CISA notes
https://nvd.nist.gov/vuln/detail/CVE-2021-22017

Description

Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.

Severity

CVSS 3.1 · CISA5.3 MEDIUM

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

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impactpartial

Exploitation Context

as of October 14, 2026

All KEV statistics→

CISA added CVE-2021-22017 to the KEV catalog 109 days after its CVE record was published.
It is one of 33 VMware entries in the CISA KEV catalog, and one of 11 added in 2022.
Its current EPSS score (49.2%) is higher than that of 50% of CISA KEV entries.

Affected Products

Vendor	Product	Affected versions
-	VMware vCenter Server, VMware Cloud Foundation	VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2

References

1 Links

Other references

https://www.vmware.com/security/advisories/VMSA-2021-0020.html

Record Details

Published

2021-09-23

Last updated

2025-10-21

Assigner (CNA)

vmware

Credited to

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CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.