CVE-2025-22226: VMware ESXi, Workstation, and Fusion Information Disclosure Vulnerability in HGFS - Potential Memory Leak Exploit

CVE-2025-22226 is a newly discovered information disclosure vulnerability affecting VMware ESXi, Workstation, and Fusion, which could allow a malicious actor with administrative privileges to leak memory from the vmx process. This vulnerability is due to an out-of-bounds read in the Host-Guest File System (HGFS), a feature that allows easy file sharing between the host and guest operating systems.

In this long read post, we will discuss the vulnerability, the affected VMware products, provide a code snippet showing the exploit, and link to the original references and patches. By understanding the details of this exploit, users and administrators can better secure their systems against potential memory leaks and the risks they may pose.

Vulnerability Details: Out-of-Bounds Read in HGFS

An out-of-bounds read occurs when a program reads data from a buffer using an index or pointer that references a memory location outside the intended data structure. This error can cause the program to return or process unrelated or sensitive information. In the case of CVE-2025-22226, the out-of-bounds read in the HGFS may leak memory from the vmx process, potentially providing a malicious actor with sensitive information.

Here is a simplified code snippet demonstrating the out-of-bounds read vulnerability in the HGFS

/* Assume buf is a buffer containing data sent from the guest operating system */
void process_hgfs_packet(buffer *buf) {
    hgfs_header *header = (hgfs_header *)buf->data;

    /* Check packet size to be in the correct range */
    if (header->packet_size > MAX_PACKET_SIZE || header->packet_size < MIN_PACKET_SIZE) {
        return; /* Invalid packet size */
    }

    /* Vulnerable Out-of-Bounds Read: Reading data outside the bounds of the buffer */
    data_to_read = MIN((header->data_size + header->offset), header->packet_size);
    read_data_from_buffer(buf, header->offset, data_to_read);
}

In the code above, the read_data_from_buffer() function reads data_to_read bytes from a given buffer starting at header->offset. The out-of-bounds read vulnerability occurs when the values of header->data_size and header->offset are such that their sum exceeds the header->packet_size value, potentially reading memory outside the intended buffer area.

Original References and Fixes

VMware has acknowledged this vulnerability and provided patches to fix the issue. The following are the official advisories related to CVE-2025-22226:

- VMware Security Advisory VMSA-2025-0001: [\[Link\]](https://www.vmware.com/security/advisories/VMSA-2025-0001.html)
- CVE-2025-22226 Details on the CVE website: [\[Link\]](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-22226)

Users and administrators are strongly encouraged to apply the patches provided by VMware, following the guidelines on the advisory pages linked above.

Conclusion

CVE-2025-22226 is a significant information disclosure vulnerability in VMware ESXi, Workstation, and Fusion that could potentially lead to memory leaks, compromising sensitive information. By understanding the details of this exploit and ensuring that appropriate fixes have been applied, users and administrators can prevent malicious actors from exploiting this vulnerability to leak memory from the vmx process.

Timeline

Published on: 03/04/2025 12:15:33 UTC
Last modified on: 03/05/2025 02:00:02 UTC