CVE-2025-41237: Critical Integer-Underflow Vulnerability in VMware Products

Overview

The cybersecurity landscape is constantly evolving, with new vulnerabilities emerging regularly. One such vulnerability, designated CVE-2025-41237, affects popular VMware products, including ESXi, Workstation, and Fusion. This vulnerability is particularly concerning due to its high severity rating and the possibility of system compromise or data leakage. As such, it is critical for system administrators and cybersecurity professionals to understand this vulnerability, its potential impacts, and the necessary steps for mitigation.
CVE-2025-41237 exploits an integer-underflow in the Virtual Machine Communication Interface (VMCI) of the affected VMware products. By exploiting this vulnerability, an attacker with local administrative privileges on a virtual machine can execute code on the host machine, potentially leading to severe consequences such as unauthorized data access or system disruption.

Vulnerability Summary

CVE ID: CVE-2025-41237
Severity: Critical (CVSS score 9.3)
Attack Vector: Local
Privileges Required: Administrative
User Interaction: None
Impact: System Compromise and Data Leakage

Affected Products

Product | Affected Versions

VMware ESXi | All versions prior to the latest patch
VMware Workstation | All versions prior to the latest patch
VMware Fusion | All versions prior to the latest patch

How the Exploit Works

The vulnerability arises from an integer-underflow in the VMCI of the affected VMware products. An integer-underflow is a condition that can occur in a computer program when an integer is decreased below its defined range. This leads to an out-of-bounds write, thereby allowing malicious actors to manipulate data and control program execution.
In the case of CVE-2025-41237, a malicious actor with local administrative privileges on a virtual machine can exploit this vulnerability to execute code as the VMX process running on the host. While on ESXi, the exploitation is contained within the VMX sandbox, on Workstation and Fusion, it may lead to code execution on the machine where Workstation or Fusion is installed.

Conceptual Example Code

While a precise exploit code for CVE-2025-41237 is not publicly available considering the critical nature of the vulnerability, a conceptual example could look something like this:

# Pseudo code demonstrating the exploit
def exploit():
# Underflow the integer
int_underflow = 0x100000000 - 1
# Craft malicious payload
payload = struct.pack('<I', int_underflow) * 1024
# Write to VMCI
vmci.write(payload)

In this conceptual example, the attacker crafts a payload that would cause an integer underflow, then writes this payload to the VMCI. This would result in out-of-bounds write, potentially leading to code execution on the host machine.