CVE-2021-34855: (Pwn2Own) Parallels Desktop Toolgate Uninitialized Memory Information Disclosure Vulnerability

Published Oct 25, 2021

Updated

This vulnerability allows local attackers to disclose sensitive information on affected installations of Parallels Desktop 16.1.3 (49160). An attacker must first obtain the ability to execute low-privileged code on the target guest system in order to exploit this vulnerability. The specific flaw exists within the Toolgate component. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the hypervisor. Was ZDI-CAN-13592.

Other sources

This vulnerability allows local attackers to disclose sensitive information on affected installations of Parallels Desktop. An attacker must first obtain the ability to execute low-privileged code on the target guest system in order to exploit this vulnerability. The specific flaw exists within the Toolgate component. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the hypervisor.

Affected Software

2 affected components

Parallels Parallels Desktop Macos=16.1.3

Parallels Desktop

Remediation

Patch Available

https://kb.parallels.com/125013

Event History

Oct 25, 2021

CVE Published

via MITRE·05:10 PM

Data Sourced

via MITRE·05:10 PM

DescriptionSeverityWeakness

Mar 24, 2025

Advisory Published

via ZDI·07:01 PM

Frequently Asked Questions

What is CVE-2021-34855?

CVE-2021-34855 is a vulnerability in Parallels Desktop 16.1.3 that allows local attackers to disclose sensitive information.

How can this vulnerability be exploited?

To exploit CVE-2021-34855, an attacker must first obtain the ability to execute low-privileged code on the target guest system.

What is the severity of CVE-2021-34855?

The severity of CVE-2021-34855 is medium with a CVSS score of 6.5.

Which software versions are affected by CVE-2021-34855?

CVE-2021-34855 affects Parallels Desktop 16.1.3.

How can I fix CVE-2021-34855?

To mitigate CVE-2021-34855, update Parallels Desktop to the latest version and follow the recommendations provided by Parallels.