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Vulnerability record · CVE-2021-45336 · published 27 December 2021

CVE-2021-45336: Avast antivirus vulnerability

Avast · Antivirus

Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.

8.8 CVSS 3.1 High EPSS 0.46% · top 63.0%
8.8CVSS 3.1 base score, v2 7.2
0.46%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021 ExploitThird Party Advisory
https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0 Vendor Advisory
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021 ExploitThird Party Advisory
https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0 Vendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-45336), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.