What’s Vulnerable › Vulnerabilities

CVE-2021-45339

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-27 · updated 2026-06-17
• Weakness: CWE-863

Description

Privilege escalation vulnerability in Avast Antivirus prior to 20.4 allows a local user to gain elevated privileges by "hollowing" trusted process which could lead to the bypassing of Avast self-defense.

Affected products

• Avast Antivirus: before 20.4 — fixed in 20.4

How to fix

Upgrade to a fixed version: Avast Antivirus 20.4. Check the vendor advisory for mitigations.

References

• https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST0
• https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0
• https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST0
• https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0

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