This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Desktop 16.1.3 (49160).

published 2021-10-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21503

cvss: 8.2; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits: 0; none known

This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Desktop 16.1.3 (49160). An attacker must first obtain the ability to execute high-privileged code on the target guest system in order to exploit this vulnerability. The specific flaw exists within the virtio-gpu virtual device. The issue results from the lack of proper validation of user-supplied data, which can result in a memory corruption condition. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the hypervisor. Was ZDI-CAN-13581.

Patch / fix

links 1

kb.parallels.com/125013 advisory

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.0	8.2	CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
NVD	3.1	8.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD	2.0	4.6	AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

Parallels Desktop

Classification

Weakness

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

References

kb.parallels.com /125013
patch, vendor-advisory
zerodayinitiative.com /advisories/ZDI-21-938/
third-party-advisory, vdb-entry

Sources

CVE List CVE-2021-34856
NVD CVE-2021-34856

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary