VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability
VMware · vCenter Server and Cloud Foundation
The vSphere Client (HTML5) in VMware vCenter Server and Cloud Foundation contains a Server-Side Request Forgery flaw caused by improper URL validation in a vCenter Server plugin. An attacker with network access to port 443 and no authentication or user interaction can send a crafted POST request to the plugin, leading to information disclosure.
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).
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 2/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 1 day after disclosure. Public exploit code (PoC-in-GitHub) appeared 20 days after disclosure.
- Disclosedday 0
- First seen exploitedVulnCheck KEV evidence+1 day
- Public exploit codePoC-in-GitHub+20 days
- Added to CISA KEVEU database agrees+12 mo
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
2 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 2Initial AccessTA0001
This vulnerability is exploited through an SSRF (Server Side Request Forgery) flaw in the vSphere Client (HTML5) of VMware's vCenter Server, affecting the vCenter Server plugin. Attackers leverage this vulnerability to gain unauthorized access by sending a crafted POST request to the vCenter Server plugin, thereby bypassing URL validation. This manipulation enables the disclosure of sensitive information. By exploiting this flaw, attackers can scan the company's internal network and retrieve specifics about open ports and services.
DiscoveryTA0007
Detection
0 rules for this CVE · 169 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2021-21973 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploit Public-Facing ApplicationT1190149 general rules
- Arcadyan Router Exploitationscriticaltest
- Citrix ADS Exploitation CVE-2020-8193 CVE-2020-8195criticaltest
- Citrix Netscaler Attack CVE-2019-19781criticaltest
- Confluence Exploitation CVE-2019-3398criticaltest
- CVE-2010-5278 Exploitation Attemptcriticaltest
- CVE-2020-0688 Exchange Exploitation via Web Logcriticaltest
- CVE-2020-10148 SolarWinds Orion API Auth Bypasscriticaltest
- CVE-2020-5902 F5 BIG-IP Exploitation Attemptcriticaltest
Network Service DiscoveryT104620 general rules
- HackTool - winPEAS Executionhightest
- HackTool - WinPwn Executionhightest
- HackTool - WinPwn Execution - ScriptBlockhightest
- Grixba Malware Reconnaissance Activityhighexperimental
- OpenCanary - Host Port Scan (SYN Scan)highexperimental
- OpenCanary - NMAP FIN Scanhighexperimental
- OpenCanary - NMAP NULL Scanhighexperimental
- OpenCanary - NMAP OS Scanhighexperimental
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX