5.3

CVE-2021-21973: VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability

CVSS: 5.3v3.1MediumKEVAnalyzed
Published 24-02-2021Last modified 21-10-2025
Open JSON

Vulnerability summary

CVE-2021-21973 is a medium (CVSS 5.3) Server-Side Request Forgery (SSRF) vulnerability in VMware vCenter Server and Cloud Foundation. It is known to be exploited: CISA lists it, first on 07-03-2022. EPSS estimates a 88.01% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities.

Overall risk
85/100
0100
Critical · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
88.01%
0%100%
Critical · +0.37 pp in 30 days
KEVListedCISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 24-02-2021
    PublishedVulnerability first disclosed.
  2. 07-03-2022
    Added to CISA KEVVMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability
  3. 21-03-2022
    CISA remediation dueApply updates per vendor instructions.
  4. 21-10-2025
    Last modifiedVulnerability information updated.

Description

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).

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

88.01%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

+0.37 pp

From 87.64% on 18-09-2026

18-09-202618-10-2026
EPSS score
88.01%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
07-03-2022
Federal due date
21-03-2022

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-21973

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Vmware2 products
  • cloud_foundation≥ 3.0, < 3.10.1.2 | ≥ 4.0, < 4.2
  • vcenter_serverEOL6.5 | 6.5:a | 6.5:b | 6.5:c | 6.5:d | 6.5:e | 6.5:f | 6.5:update1d | 6.5:update1e | 6.5:update1g | 6.5:update2 | 6.5:update2b | 6.5:update2c | 6.5:update2d | 6.5:update2g | 6.5:update3 | 6.5:update3d | 6.5:update3f | 6.5:update3k | 6.7 | 6.7:a | 6.7:b | 6.7:d | 6.7:update1 | 6.7:update1b | 6.7:update2 | 6.7:update2a | 6.7:update2c | 6.7:update3 | 6.7:update3a | 6.7:update3b | 6.7:update3f | 6.7:update3g | 6.7:update3j | 7.0 | 7.0:a | 7.0:b | 7.0:c | 7.0:d | 7.0:update1 | 7.0:update1a

1 vendor · 2 products

References

2 links