Broadcom Patches Critical ESXi Vulnerability Enabling Host Code Execution

VMware ESX, Workstation, and Fusion contain an out-of-bounds read vulnerability. A malicious actor with VM deployment privileges could trigger an out-of-bounds read, potentially leading to information disclosure or more likely a Denial-of-Service (DoS) condition of the host process. On Workstation and Fusion, the impact of this vulnerability is restricted to information disclosure.

VMware ESX contains an insufficient logging vulnerability. A malicious administrator could exploit this issue to perform certain operations without them being logged.

VMware ESX contains an out-of-bounds write vulnerability in the VMXNET3 virtual network adapter. A malicious actor with local administrative privileges on a virtual machine with VMXNET3 virtual network adapter may exploit this issue to execute code on the host. Non VMXNET3 virtual adapters are not affected by this issue.

VMware vCenter contains an authentication bypass vulnerability in the VMware Directory Service. A malicious actor with network access to vCenter may exploit this issue to bypass authentication and gain unauthorized access to the system.

CVE-2026-59310 is a directory traversal (CWE-22) vulnerability in the Syslog server component of VMware vCenter Server, rated critical at CVSS 9.8. It can be triggered over the network without authentication or user interaction, allowing a malicious actor with network access to vCenter to achieve arbitrary code execution. An attacker who exploits it gains code execution on the vCenter appliance, and reported campaigns show it has been used to establish persistent remote access and, by a suspected China-nexus actor, to deploy Babuk ransomware. Any organization running an affected version of vCenter Server is exposed, especially where the management interface is reachable from the internet; the available data does not specify affected version ranges. Exploitation is confirmed in the wild: CISA added the flaw to its Known Exploited Vulnerabilities catalog on 2026-08-18, it was reportedly exploited just five days after disclosure, and EPSS estimates a 45.9% probability of exploitation within 30 days (99th percentile).

Do: Upgrade vCenter Server to the patched release identified in Broadcom's advisory (no specific version ranges are provided in this data) and prioritize any vCenter that is internet-facing, in line with CISA KEV and BOD 26-04 requirements for federal agencies. Until patched, restrict access to the vCenter management interface to trusted networks and verify whether the vCenter Syslog server is enabled. Hunt for compromise indicators, including unexplained remote-access persistence and Babuk ransomware artifacts, given the documented China-nexus exploitation.