Page generated: 11 Nov 2026, 04:03 UTC
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CVE-2021-21973

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 leadi…

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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 5.3 (MEDIUM) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
8.2/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 5.3: +0.79
  • Fresh EPSS: 88.01%: +0.44

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 6 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

Barracuda Blog
Press · 03 Sep 2026, 07:00 · Threat Spotlight: Unpatched software vulnerabilities - Barracuda Blog
Barracuda Networks Blog
Press · 09 Dec 2025, 08:00 · Barracuda detects increased probing for Microsoft Exchange vulnerabilities - Barracuda Networks Blog
GreyNoise
Press · 11 Mar 2025, 07:00 · New SSRF Exploitation Surge Serves as a Reminder of 2019 Capital One Breach - GreyNoise
www.trendmicro.com
Press · 03 Dec 2021, 08:00 · Vulnerabilities Exploited for Monero Mining Malware Delivered via GitHub, Netlify - www.trendmicro.com
Rapid7
Press · 24 Feb 2021, 08:00 · VMware vCenter Server CVE-2021-21972 Remote Code Execution Vulnerability: What You Need to Know - Rapid7
See all 6 source documents
The Hacker News
Press · 24 Feb 2021, 08:00 · Critical RCE Flaws Affect VMware ESXi and vSphere Client — Patch Now - The Hacker News

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 8.2 (2026-11-02 15:12). The curve appears once the score changes.

Public exploit evidence

0

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 5.3; EPSS 88.0%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, no user interaction.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 13:58:23.782764+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
First press mention
24 Feb 2021, 08:00
Published
24 Feb 2021, 16:42
Added to the CISA KEV catalog
07 Mar 2022, 00:00
Latest press mention
03 Sep 2026, 07:00
Score calculated
05 Nov 2026, 13:58