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CVE-2021-21973

94
FAUCET Score

CVE-2021-21973 is a Server-Side Request Forgery (SSRF) vulnerability in the vSphere Client (HTML5) affecting VMware vCenter Server and Cloud Foundation versions. This flaw, stemming from improper URL validation in a vCenter Server plugin, allows an unauthenticated attacker with network access to port 443 to send a POST request, leading to information disclosure. Rated as Medium severity (CVSS 5.3), its low attack complexity and network-based vector make it a significant risk, as reflected by its high EPSS and FAUCET Risk Scores. This vulnerability is actively exploited in the wild and has garnered substantial community discussion and media coverage, with Nuclei templates available for detection.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.0, < 3.10.1.2CPE matchmatch criteria
cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
>= 4.0, < 4.2CPE matchmatch criteria
cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
6.5CPE matchmatch criteria
cpe:2.3:a:vmware:vcenter_server:6.5:-:*:*:*:*:*:*
6.5CPE matchmatch criteria
cpe:2.3:a:vmware:vcenter_server:6.5:a:*:*:*:*:*:*
6.5CPE matchmatch criteria
cpe:2.3:a:vmware:vcenter_server:6.5:b:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
88.01%
Probability of exploitation in next 30 days
EPSS Percentile
99.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
Added to KEV · Mar 7, 2022
Nuclei: CVE-2021-21973 · Jan 27, 2022
This CVE's current EPSS score of 0.8801 is in the 100th percentile among its peer group of 23,725 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

denopatch availablevia llm_extracted
View patch
invoiceplanepatch availablevia llm_extracted
View patch
pjsippatch availablevia llm_extracted
View patch
vmwarevendor investigatingvia nvd_reference
View patch

Vendor Advisories (3)

pjsipllm-pjsip-a5819dd28f75fbf7CRITICAL

VMware ESXi and vSphere Client Vulnerabilities (VMSA-2021-0002)

Jan 1, 2021
invoiceplanellm-invoiceplane-3d0b55a6e45529bdCRITICAL

Per VMware security advisory VMSA-2021-0002, VMware received reports of multiple vulnerabilities in VMware ESXi and vSphere Client (HTML5).

denollm-deno-23a2358c060f5bbbCRITICAL

VMware ESXi and vSphere Client Multiple Vulnerabilities

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
vmware.com / security/advisories/VMSA-2021-0002.html
Vendor Advisory