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Hi, I'm Sharon, a product manager at Chaitin Tech. We build SafeLine, an open-source Web Application Firewall built for real-world threats. While SafeLine focuses on HTTP-layer protection, our emergency response center monitors and responds to RCE and authentication vulnerabilities across the stack to help developers stay safe.
In July 2025, VMware issued a high-priority security advisory (VMSA-2025-0013) addressing four critical vulnerabilities affecting VMware ESXi, Workstation, Fusion, and Tools. These flaws—tracked as CVE-2025-41236, CVE-2025-41237, CVE-2025-41238, and CVE-2025-41239—could allow remote code execution (RCE) and virtual machine (VM) escape, posing a major risk to virtualization infrastructure.
What’s Affected?
-
VMware ESXi: 8.0.x <
ESXi80U2e-24789317, 7.0.x <ESXi70U3w-24784741 -
VMware Workstation: 17.0.x <
17.6.4 -
VMware Fusion: 13.0.x <
13.6.4
Vulnerability Breakdown
CVE-2025-41236 – VMXNET3 Integer Overflow
- CVSS Score: 9.3 (Critical)
- A flaw in the VMXNET3 virtual network adapter allows attackers with admin access inside the guest VM to exploit an integer overflow, leading to code execution on the host.
- Only affects VMs with the VMXNET3 adapter.
CVE-2025-41237 – VMCI Integer Underflow
- CVSS Score: 9.3 (Critical)
- A vulnerability in the Virtual Machine Communication Interface (VMCI) allows out-of-bounds writes, potentially leading to RCE on the host through the VMX process.
- On ESXi, the attack stays within the VMX sandbox. On Workstation and Fusion, it could break out to the host OS.
CVE-2025-41238 – PVSCSI Heap Overflow
- CVSS Score: 9.3 (Critical)
- Exploitable heap overflow in the PVSCSI controller (paravirtual SCSI), leading to code execution from a guest VM on the host.
- On ESXi, only exploitable under unsupported configurations; on Workstation/Fusion, could lead to host-level RCE.
CVE-2025-41239 – vSockets Info Leak
- Information disclosure caused by use of uninitialized memory in vSockets.
- Could leak sensitive memory data to attackers with guest admin access.
Why It Matters
- VM Escape: Attackers can break out of a sandboxed VM and compromise the host, potentially affecting the entire virtualized environment.
- Data Leak: Sensitive memory information may be exposed.
- Privilege Requirement: All four vulnerabilities require local administrator access inside the VM to exploit.
- No User Interaction Required: Exploits do not need user interaction once access is obtained.
Patch Now
VMware recommends upgrading to the following safe versions immediately:
-
VMware ESXi:
ESXi80U2e-24789317orESXi70U3w-24784741 -
VMware Workstation:
17.6.4 -
VMware Fusion:
13.6.4
Official Advisory – VMSA-2025-0013
Timeline
- July 2025: VMware published VMSA-2025-0013
- July 17, 2025: Longterm Security Emergency Response Center issued this risk alert
Final Recommendations
- Upgrade vulnerable systems immediately
- Review access control policies
- Restrict unnecessary network access to hypervisors
- Monitor systems for signs of VM escape or suspicious VM behavior
These are serious vulnerabilities that could compromise the core isolation guarantees of your virtual infrastructure. Don’t delay—patch today.
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