Broadcom Patches Five Critical VMware Vulnerabilities Including CVSS 9.8 Authentication Bypass

Broadcom has released fixes for five vulnerabilities across multiple VMware products that could enable authentication bypass, remote code execution, and virtual machine escapes. The most severe issue, CVE-2026-59309 with a CVSS score of 9.8, resides in the VMware Directory Service component of vCenter and allows an attacker with network access to bypass authentication entirely. Successful compromise of vCenter grants control over hosts, virtual machines, networks, and storage, posing severe risks to enterprise environments. A second critical flaw, CVE-2026-47876, affects the VMXNET3 virtual adapter in ESX and permits an attacker with administrative privileges inside a guest VM to perform an out-of-bounds write and execute code on the hypervisor host. Additional patches address an unauthorized memory read in ESX, Workstation, and Fusion, along with insufficient logging that could conceal administrative actions. No workarounds exist, and administrators must apply the specified updates to vCenter, ESX, Cloud Foundation, Workstation, and Fusion.

BoletimSecTranslated from Portuguese

Read at source

Broadcom has issued security updates addressing five vulnerabilities in VMware products that could allow authentication bypass, code execution, and virtual machine escapes in corporate virtualized environments.

The most critical flaw, tracked as CVE-2026-59309 with a CVSS score of 9.8, affects the VMware Directory Service component of vCenter. An attacker with network access to the server can bypass authentication mechanisms and gain access without valid credentials.

Because vCenter manages hosts, virtual machines, networks, and storage, unauthorized access carries significant risk, potentially enabling infrastructure changes, service disruption, and compromise of business workloads.

Another high-severity issue, CVE-2026-47876, resides in the VMXNET3 virtual network adapter of ESX. An attacker with administrative privileges inside a virtual machine can exploit an out-of-bounds write condition to execute arbitrary code directly on the hypervisor host.

The update package also resolves an unauthorized memory read vulnerability affecting ESX, Workstation, and Fusion, as well as a logging deficiency that could allow certain administrative actions to go undetected.

No temporary mitigations are available. Administrators are advised to update vCenter to versions 9.1.0.0300, 9.0.2.0100, or 8.0 U3k, apply corresponding patches to ESX hosts and Cloud Foundation, and upgrade Workstation and Fusion to version 26H1.

Meridian digestThe week's most consequential security stories, distilled into one briefing.See the digest

More in Vulnerabilities & Exploits

Telegram for Android Patches Voice Call Vulnerability Enabling Code Execution
Yandex Patches Millions of Stations After eMudhra Certificate Keys Compromised
Cisco ASA and FTD Face DoS Vulnerability in SSL VPN Already Exploited in the Wild