CVE-2021-45339: 
Avast Antivirus vulnerability analysis and mitigation

A privilege escalation vulnerability was identified in Avast Antivirus versions prior to 20.4. The vulnerability allows a local user to gain elevated privileges by 'hollowing' trusted processes, which could lead to bypassing Avast's self-defense mechanisms (NVD, AttackerKB).

The vulnerability has been assigned a CVSS v3.1 Base Score of 7.8 (High), with the following vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. The attack requires local access with low privilege requirements and no user interaction. The vulnerability impacts confidentiality, integrity, and availability, all rated as High (NVD).

When successfully exploited, this vulnerability allows an attacker to gain elevated system privileges, potentially leading to full system compromise. The attacker can bypass Avast's self-defense mechanisms, which are designed to protect the antivirus software from tampering (NVD).

The vulnerability has been patched in Avast Antivirus version 20.4 and later. Users are advised to update their Avast Antivirus software to the latest version to mitigate this vulnerability (NVD).