CVE-2021-21972
Path Traversal in Vmware Vcenter Server 6.5 … 7.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2021-21972 is a critical-severity Path Traversal (CWE-22) vulnerability in Vmware Vcenter Server. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
The vulnerability is a remote code execution flaw in the vSphere Client (HTML5) component of VMware vCenter Server, specifically within a server plugin. It stems from improper handling that permits path traversal (CWE-22) and affects VMware vCenter Server 7.x releases prior to 7.0 U1c, 6.7 releases prior to 6.7 U3l, and 6.5 releases prior to 6.5 U3n, as well as VMware Cloud Foundation 4.x releases prior to 4.2 and 3.x releases prior to 3.10.1.2. The issue carries a CVSS score of 9.8, reflecting network-accessible, unauthenticated exploitation with full impact on confidentiality, integrity, and availability.
An attacker with network connectivity to the vCenter Server on TCP port 443 can send specially crafted requests to upload arbitrary files and subsequently execute operating-system commands with unrestricted privileges on the underlying host. No authentication or user interaction is required, enabling complete compromise of the vCenter instance and any connected infrastructure.
The official VMware advisory VMSA-2021-0002 recommends immediate application of the listed patches that remediate the plugin flaw; organizations should also restrict external exposure of port 443 and monitor for anomalous file-upload activity. Public exploit code demonstrating arbitrary file upload and remote code execution against the affected versions has been published, confirming that working attacks are readily available.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-9143
Vulnerability Data
The vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin. 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…
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hosts vCenter Server. 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).
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Validates pathnames and filenames to prevent traversal outside intended directories.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.