CVE-2025-62624: VMware ESXi Privilege Escalation Flaw

CVE-2025-62624 Overview

CVE-2025-62624 is a heap-based buffer overflow [CWE-122] affecting the ionic cloud driver shipped with VMware ESXi. An authenticated local attacker with low privileges can corrupt heap memory inside the driver and escalate privileges. Successful exploitation may lead to arbitrary code execution within the hypervisor context.

The issue is referenced in the AMD Security Bulletin AMD-SB-2001, which covers the Pensando-derived ionic networking driver. Exploitation requires local access and high attack complexity, but the impact spans confidentiality, integrity, and availability across the affected system.

Critical Impact

A local attacker can trigger a heap overflow in the ionic cloud driver to escalate privileges and execute arbitrary code on the ESXi host.

Affected Products

• VMware ESXi hosts using the ionic cloud driver
• AMD Pensando ionic network adapters and associated drivers (see AMD-SB-2001)
• Hypervisor deployments running the vulnerable driver build

Discovery Timeline

• 2026-05-13 - CVE-2025-62624 published to NVD
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2025-62624

Vulnerability Analysis

The vulnerability is a heap-based buffer overflow classified under [CWE-122]. The defect resides in the ionic cloud driver, a kernel-mode component used by ESXi to interface with AMD Pensando network adapters. Because the driver runs with elevated privileges inside the hypervisor, memory corruption within its address space can be leveraged to escalate from a low-privileged local context to full code execution on the host.

The AMD advisory categorizes the issue as enabling privilege escalation and arbitrary code execution. The attack vector is local, meaning an adversary needs an existing foothold on the system, such as access to a guest interface or management plane that reaches the driver.

Root Cause

The root cause is improper bounds enforcement when the ionic driver writes to a heap-allocated buffer. When attacker-controlled input exceeds the allocation size, adjacent heap metadata and objects are overwritten. This corruption can be shaped to hijack control flow or modify privileged data structures used by the driver.

Attack Vector

An attacker with local, low-privileged access issues crafted requests or ioctl-style operations to the ionic driver. The malformed inputs trigger the unchecked heap write, corrupting kernel heap memory. The attacker then leverages the corruption to elevate privileges and run code in the driver's context. No verified public proof-of-concept exploit is available.

No verified exploitation code is available for CVE-2025-62624. Refer to the AMD Security Bulletin AMD-SB-2001 for vendor technical context.

Detection Methods for CVE-2025-62624

Indicators of Compromise

• Unexpected ESXi host crashes, PSODs, or kernel panics referencing the ionic driver module
• Anomalous loading or reloading of the ionic driver outside of patch maintenance windows
• Privilege transitions on the ESXi host that lack a corresponding authenticated administrative session

Detection Strategies

• Monitor vmkernel.log and vmksummary.log for ionic driver faults, assertion failures, or heap corruption stack traces
• Baseline driver versions across the ESXi fleet and alert when ionic driver hashes or versions deviate
• Correlate local logon events on ESXi management interfaces with subsequent driver-level errors

Monitoring Recommendations

• Forward ESXi host logs to a centralized analytics platform for retention and correlation
• Track ESXCLI and API calls that interact with network driver subsystems for anomalies
• Alert on new processes spawned with hypervisor-level privileges following local authentication events

How to Mitigate CVE-2025-62624

Immediate Actions Required

• Inventory ESXi hosts that load the ionic cloud driver and identify those backing AMD Pensando hardware
• Restrict local and management-plane access to ESXi hosts to a minimal set of administrative accounts
• Apply the driver and firmware updates referenced in AMD-SB-2001 as soon as they are validated for your environment

Patch Information

Consult the AMD Security Bulletin AMD-SB-2001 for the specific driver and firmware versions that remediate CVE-2025-62624. Coordinate with VMware support to confirm the supported ionic driver build for your ESXi release before deployment.

Workarounds

• Limit ESXi shell, SSH, and API access to trusted administrators on isolated management networks
• Disable or unload the ionic driver on hosts where the Pensando adapter is not in active use, where operationally feasible
• Enforce strong authentication and least-privilege role assignments for all accounts able to reach the hypervisor

# Verify the ionic driver version loaded on an ESXi host
esxcli system module list | grep -i ionic
esxcli system module get -m ionic_en