CVE-2021-34856

Hypervisor code execution via virtio-gpu memory corruption

Published Oct 25, 2021 · Updated Aug 4, 2024

Memory corruption in Parallels Desktop 16.1.3 (49160) allows local users to execute arbitrary code in the hypervisor context. The virtio-gpu virtual device fails to validate guest-supplied data before processing it, producing a memory-corruption condition. Exploitation requires high-privileged code execution in a guest system and crosses the guest boundary into the hypervisor.

CVSS severity8.2
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Parallels Desktop 16.1.3 (49160) allows local users to execute arbitrary code in the hypervisor context. The virtio-gpu virtual device fails to validate guest-supplied data before processing it, producing a memory-corruption condition. Exploitation requires high-privileged code execution in a guest system and crosses the guest boundary into the hypervisor.

The record

CVE
CVE-2021-34856
Published
Oct 25, 2021
Updated
Aug 4, 2024
Vendor
Parallels
Product
Parallels Desktop
Classifications
CWE-119, CWE-787, T1068
Attack vector
local
Privileges
admin

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

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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 privilegesadmin

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
8.2Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
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

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Your stack

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