CVE-2021-22005

CVE-2021-22005 is a path-traversal (CWE-23) file upload flaw in the Analytics service of VMware vCenter Server, the central management platform for VMware vSphere environments. An attacker with network access to the server's HTTPS port (443) can send crafted upload requests that traverse directories and write arbitrary files, achieving critical remote code execution on the vCenter host (VMware rated the flaw critical; this dataset's CVSS field was still pending). Successful exploitation gives attackers control of the vSphere management plane and, in practice, the ESXi hosts and virtual machines it manages, making it a high-value target for ransomware operators. All on-premises vCenter Server deployments of the affected versions are exposed, with internet-reachable instances at greatest risk since network access to port 443 is the only prerequisite. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use, EPSS assigns a ~100% (100th percentile) probability of exploitation within 30 days, and no public proof-of-concept was known at the time of this dataset.

What to do: Upgrade to the fixed releases in VMware advisory VMSA-2021-0020 (vCenter Server 7.0 U2c, 6.7 U3o, or 6.5 U3q), or apply the vendor workaround of disabling the Analytics service if patching must be delayed. Restrict exposure of port 443 to untrusted networks, and hunt exposed vCenter servers for compromise indicators (webshells, unexpected accounts or processes) since exploitation is confirmed and ransomware campaigns are known to use this flaw.