CVE-2021-27241 Path traversal in Premium Security

What is CVE-2021-27241?

CVE-2021-27241 is a medium-severity path traversal vulnerability in Avast Premium Security, published on 29 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

This vulnerability allows local attackers to delete arbitrary directories on affected installations of Avast Premium Security 20.8.2429 (Build 20.8.5653.561). 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 AvastSvc.exe module. By creating a directory junction, an attacker can abuse the service to delete a directory. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-12082.

Weakness: CWE-59

Which versions are affected by CVE-2021-27241?

It affects 1 product.

Products include Avast Premium Security.

How do I fix CVE-2021-27241?

No fix has been published for CVE-2021-27241 yet. Limit exposure of the affected software until one is available.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2021-27241 being exploited?

There is no known exploitation of CVE-2021-27241 in the wild and no public exploit code.

Other vulnerabilities in Avast Premium Security

• CVE-2023-42125 Avast Premium Security Sandbox Protection Link Following Privilege Escalation Vulnerability High 7.8
• CVE-2019-18894 Command injection in n/a High 7.8
• CVE-2022-28964 Path traversal in n/a High 7.1
• CVE-2022-28965 Other in n/a Medium 6.5
• CVE-2023-42124 Avast Premium Security Sandbox Protection Incorrect Authorization Privilege Escalation Vulnerability Medium 5.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-76qj-3c6g-8v48.