A newly disclosed argument injection vulnerability in Parallels Desktop for Mac allows unprivileged local users to elevate their access to root privileges on host systems.
Tracked as CVE-2026-90894 and assigned the moniker “ParaShells,” the security defect specifically impacts Parallels Desktop for Mac version 26.4.0 running on Apple Silicon ARM-based processors. The vulnerability exists due to a combination of a world-writable Unix socket, weak local-client authentication, and flawed argument handling within the appliance extraction path.
Exploitation requires the target host to run a vulnerable build of the virtualization software with the active prl_disp_service launch daemon and its corresponding /var/run/prl_disp_service.socket socket file present. An attacker operating under any low-privileged local user account can exploit the flaw without requiring a virtual machine to be actively running.
JFrog vulnerability research team lead Yuval Moravchick explained the attack chain mechanics during disclosure, stating, “The exploit combines its world-writable Unix socket with weak local-client authentication and argument injection in the appliance extraction path.” Moravchick further detailed that the process involves a login that trusts peer credentials rather than a Team ID, and an unpack path building tar arguments via Qt string splitting where quotes in the parent path inject --use-compress-program=.
As a result, macOS tar processes execute arbitrary attacker scripts with user ID 0, granting full administrative control over the machine. Moravchick warned that the risk level scales significantly on shared corporate and university computers, as well as developer laptops vulnerable to poisoned Homebrew formulae or malicious npm preinstall scripts.
Parallels manufacturer Alludo addressed the vulnerability in Parallels Desktop version 27.0.0, released in early September 2026. Security teams managing Apple hardware fleets are advised to audit endpoints for vulnerable versions of the software and update immediately to version 27.0.0 or higher.