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Full vulnerability report · 2021
CVE-2021-21973High confidence

VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability

VMware · vCenter Server and Cloud Foundation

5.3MediumCVSS 3.1
Recommended action
Protect now

CISA confirms exploitation in the wild and lists 2022-03-21 as the remediation due date.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 7 Mar 2022

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 88.01% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs VMware vCenter Server and Cloud Foundation and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-9144

CISA KEV mirrored by ENISA

The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue by sending a POST request to vCenter Server plugin leading to information disclosure. This affects: VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 7 Mar 2022. Evidence sources: cisa_kev.
ENISA score
5.3 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionProtect now

CISA confirms exploitation in the wild and lists 2022-03-21 as the remediation due date.

Fix not verified
01

What, why and how

VMware vCenter Server and Cloud Foundation Server contain a SSRF vulnerability due to improper validation of URLs in a vCenter Server plugin. This allows for information disclosure.

What

VMware vCenter Server and Cloud Foundation Server contain a SSRF vulnerability due to improper validation of URLs in a vCenter Server plugin. This allows for information disclosure.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may obtain information outside the intended access boundary.

What

VMware vCenter Server and Cloud Foundation Server contain a SSRF vulnerability due to improper validation of URLs in a vCenter Server plugin. This allows for information disclosure.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may obtain information outside the intended access boundary.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-03-07.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Server-Side Request Forgery (SSRF) → obtain information outside the intended access boundary
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-918 ↗

CWE-918: Server-Side Request Forgery (SSRF). The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-918CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2021-9144Known-exploited evidence recorded

The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue by sending a POST request to vCenter Server plugin leading to information disclosure. This affects: VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20210303Security Bulletin 03 Mar 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 03 Mar 2021, published on 3 March 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-145Multiples vulnérabilités dans les produits VMWare

De multiples vulnérabilités ont été découvertes dans les produits VMWare. Elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001342VMware vCenter Server および Cloud Foundation におけるサーバサイドのリクエストフォージェリの脆弱性

VMware vCenter Server および Cloud Foundation には、サーバサイドのリクエストフォージェリの脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5268VMware 제품 취약점 보안 업데이트 권고

#### VMware 제품 취약점 보안 업데이트 권고 2021.02.25 ##### □ 개요 o VMware 社는 자사 제품에서 발생하는 취약점을 해결한 보안 업데이트 발표 [1] o 공격자는 해당 취약점을 악용하여 원격코드실행 등의 피해를 발생시킬 수 있으므로, 최신버전으로 업데이트 권고 ##### □ 주요 내용 [1] CVE ID 내용 심각도(CVSSv3) CVE-2021-21972 vCenter 서버 플러그인에서 발생하는 원격코드실행 취약점 Critical(9.8) CVE-2021-21973 vCenter 서버 플러그인에서 URL에 대한 검증이 미흡하여 발생하는 SSRF 취약점 Moderate(5.3) CVE-2021-21974 ESXI의 OpenSLP에서 힙오버플로우로 인해 발생하는 원격코드실행 취약점 High(8.8) ##### □ 영향받는 제품 및 해결 버전 제품명 플랫폼 영향 받는 버전 최신 패치 버전 vCenter Server 모든 플랫폼 6.5 6.5 U3n 6.7 6.7 U3l 7.0 7.0 U1c Cloud Foundation (vCenter Server) 모든 플랫폼 3.x 3.10.1.2 4.x 4.2 ESXi 모든 플랫폼 6.5 ESXi650-202102101-SG 6.7 ESXi670-202102401-SG 7.0 ESXi70U1c-17325551 Cloud Foundation (ESXi) 모든 플랫폼 3.x [2] 참고 4.x 4.2 ##### □ 해결 방안 o 참고사이트[1]에 명시되어 있는 ‘Reference’ 내용을 참고하여 패치 적용 ##### □ 기타 문의사항 o 한국인터넷진흥원 사이버민원센터: 국번없이 118 [참고사이트] [1] https://www.vmware.com/security/advisories/VMSA-2021-0002.html [2] https://kb.vmware.com/s/arti

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
  • VMware vCenter Server: 7.x before 7.0 U1c, 6.7 before 6.7 U3l, 6.5 before 6.5 U3n
  • VMware Cloud Foundation: 4.x before 4.2, 3.x before 3.10.1.2
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 24 Feb 2021 · Last source change 21 Oct 2025, 23:25 UTC · CWE-918 · Server-Side Request Forgery (SSRF)

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-9144
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    7.x before 7.0 U1c; 6.7 before 6.7 U3l; 6.5 before 6.5 U3n; 4.x before 4.2; 3.x before 3.10.1.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    VMware vCenter Server: 7.x before 7.0 U1c, 6.7 before 6.7 U3l, 6.5 before 6.5 U3n; VMware Cloud Foundation: 4.x before 4.2, 3.x before 3.10.1.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
ENISA EUVD · EUVD-2021-9144↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-21973 · cve.blacktree.nl