What is the CVSS score of CVE-2021-22017?

CVE-2021-22017 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 47.6%.

Is there a public PoC exploit available for CVE-2021-22017?

Yes, a public proof-of-concept exploit is available for CVE-2021-22017. Prioritise patching immediately. EPSS: 47.6%.

Is there a patch available for CVE-2021-22017?

Yes, a patch is available for CVE-2021-22017. Update the affected software to the latest version immediately.

Vcenter Server CVE-2021-22017

MEDIUM

2021-09-23 security@vmware.com

Authentication Bypass VMware Vcenter Server

5.3

CVSS 3.1 · NVD

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Vulnerability Assessment

Impact	CVSS score of 5.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: In CISA KEV with patch available.

Exploited in the wild (CISA KEV) Patch available 47.6% exploitation probability (EPSS)

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AnalysisAI

Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

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. Affected products include: Vmware Vcenter Server.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.3 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Added to CISA KEV

Jul 14, 2026 - 04:22 CISA

CVE Published

Sep 23, 2021 - 13:15 nvd

MEDIUM 5.3

DescriptionNVD

Threat Intelligence Overview

EPSS Score

47.6%

Top 1% exploitable

Exploit

POC

Public exploit code exists

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

CISA KEV

EPSS POC (1)

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV Yes

Public POC Yes

EPSS 47.6%

Patch available Yes

Active threat Yes

Deciding rule

In CISA KEV with patch available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Immediate

Exploitation· derived

Active

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact· derived

High

Priority Score

144

Low Medium High Critical

KEV: +50

EPSS: +48

CVSS: +26

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:a:vmware:vcenter_server:6.7:-:*:*:*:*:*:*

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References

Advisories & patches

PATCH https://www.vmware.com/security/advisories/VMSA-2021-0020.html REF https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017

Search Externally

GitHub PoC

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