Page generated: 07 Nov 2026, 04:47 UTC
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CVE-2021-21985

The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. A malicious actor with network access to port 443 may exploit this issue to execute com…

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The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server.
CVSS 9.8 (CRITICAL) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
9.0/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 9.8: +1.47
  • Fresh EPSS: 100.00%: +0.50

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

Sources: 11 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

Halcyon Anti-Ransomware Platform
Press · 30 Apr 2026, 07:00 · RansomHouse - Halcyon Anti-Ransomware Platform
TechTarget
Press · 15 May 2023, 07:00 · CrowdStrike warns of rise in VMware ESXi hypervisor attacks - TechTarget
www.trendmicro.com
Press · 03 Dec 2021, 08:00 · Vulnerabilities Exploited for Monero Mining Malware Delivered via GitHub, Netlify - www.trendmicro.com
www.trendmicro.com
Press · 03 Dec 2021, 08:00 · Vulnerabilities Exploited for Monero Mining Malware Delivered via GitHub, Netlify - www.trendmicro.com
Rapid7
Press · 21 Sep 2021, 07:00 · Critical vCenter Server File Upload Vulnerability (CVE-2021-22005) - Rapid7
See all 11 source documents
Unit 42
Press · 17 Sep 2021, 07:00 · Network Security Trends: May-July 2021 - Unit 42
The Hacker News
Press · 29 Jul 2021, 07:00 · Top 30 Critical Security Vulnerabilities Most Exploited by Hackers - The Hacker News
Qualys
Press · 28 Jul 2021, 07:00 · CISA Alert: Top Routinely Exploited Vulnerabilities - Qualys
Rapid7
Press · 16 Jul 2021, 07:00 · Metasploit Wrap-Up: July 16, 2021 - Rapid7
Cisco Talos Blog
Press · 10 Jun 2021, 07:00 · Threat Source newsletter (June 10, 2021) - Cisco Talos Blog
McAfee
Press · 10 Jun 2021, 07:00 · Are Virtual Machines the New Gold for Cyber Criminals? - McAfee

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 9.0 (2026-11-02 15:12). The curve appears once the score changes.

Public exploit evidence

4

Public exploit entries / repo candidates

See 4 repos with metrics
RepositoryStarsForksLanguageUpdated
alt3kx/CVE-2021-21985_PoC21449Lua19 Jan 2023, 16:24
testanull/Project_CVE-2021-21985_PoC285Python07 Jun 2021, 04:00
sknux/CVE-2021-21985_PoC31Shell09 Nov 2021, 19:14
aristosMiliaressis/CVE-2021-2198500PowerShell11 Jul 2021, 20:39
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 9.8; EPSS 100.0%
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
Published
26 May 2021, 14:04
First press mention
10 Jun 2021, 07:00
Added to the CISA KEV catalog
03 Nov 2021, 00:00
Latest press mention
30 Apr 2026, 07:00
Score calculated
05 Nov 2026, 13:58
PoCs on GitHub
4 repositories