CVE-2021-34864

Guest-to-hypervisor code execution via improper access control

Published Oct 25, 2021 · Updated Aug 4, 2024

Improper access control in Parallels Desktop 16.1.3 (49160) allows local users in a guest to execute code in the hypervisor. WinAppHelper fails to enforce the privilege boundary when handling requests from low-privileged guest code; no more specific operation has been published. Exploitation requires Parallels Tools and guest code execution; default Mac-to-VM folder sharing also exposes host files to the guest.

CVSS severity8.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper access control in Parallels Desktop 16.1.3 (49160) allows local users in a guest to execute code in the hypervisor. WinAppHelper fails to enforce the privilege boundary when handling requests from low-privileged guest code; no more specific operation has been published. Exploitation requires Parallels Tools and guest code execution; default Mac-to-VM folder sharing also exposes host files to the guest.

The record

CVE
CVE-2021-34864
Published
Oct 25, 2021
Updated
Aug 4, 2024
Vendor
Parallels
Product
Parallels Desktop
Classifications
CWE-284, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.1.3 (49160)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Parallels · Parallels Desktopversion=16.1.3 (49160)

Published CVSS scores

4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
8.8Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo