Parallels RAS Client RDP Backend Service Exposed Dangerous Function Local Privilege Escalation Vulnerability

August 11th, 2026
ZDI-26-554 ZDI-CAN-29220

CVE ID

CVE-2026-13121

CVSS Score

7.8 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors

Parallels

Affected Products

RAS Client

Vulnerability Details

This vulnerability allows local attackers to escalate privileges on affected installations of Parallels RAS Client. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the RAS RDP Backend Service. The issue results from an exposed dangerous function. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM.

Additional Details

Fixed in version 21.2 (https://kb.parallels.com/en/131037#section7)


Disclosure Timeline

  • 2026-02-25 - Vulnerability reported to vendor
  • 2026-08-11 - Coordinated public release of advisory
  • 2026-08-11 - Advisory Updated

Credit

khongtrang

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