PoC Exploit Released for Critical VMware Flaw That Could Enable Guest-to-Host Code Execution

A security researcher published a public proof-of-concept for CVE-2026-59346, a critical vulnerability in VMware's VMXNET3 TCP Segmentation Offload that can cause a guest-controlled heap overflow in the host vmware-vmx process and potentially enable host code execution; the PoC currently produces host crashes (SIGSEGV) rather than a complete guest escape. Broadcom assigned a CVSSv3 score of 9.3, ZDI rated it 7.5, and Broadcom released fixes in Workstation/Fusion version 26H1u1 (September 3, 2026); exploitation requires administrative privileges in the guest and an accessible VMXNET3 adapter, so administrators should apply patches and restrict testing to isolated environments.