#VU28338 Time-of-check Time-of-use (TOCTOU) Race Condition

Published: 2021-03-07

Vulnerability identifier: #VU28338

Vulnerability risk: Low

CVSSv3.1: 6.6 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-3957


Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
VMware Fusion
Client/Desktop applications / Virtualization software
Client/Desktop applications / Software for system administration
VMware Horizon Client
Client/Desktop applications / Software for system administration

Vendor: VMware, Inc


The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a Time-of-check Time-of-use (TOCTOU) issue in the service opener. An local user can gain elevated privileges on the target system.

Install updates from vendor's website.

Vulnerable software versions

VMware Fusion: 11.0.0 - 11.5.3

VMRC: 8.0.0 - 11.1.0

VMware Horizon Client: 3.0.0 - 5.4

External links

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

Latest bulletins with this vulnerability