HOMEVULNERABILITIESCVE-2021-45336
HIGH

CVE-2021-45336

NVD-CWE-noinfoPublished: December 27, 2021· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-45336 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeChanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected Vendors & Products

avast1 product(s)
antivirus
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021-AVST5
ADVISORYhttps://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0
ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021-AVST5
ADVISORYhttps://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0

All References (4)

→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021-AVST5Exploit · Third Party Advisory
→
https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0Vendor Advisory
→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST3%20%26%20CVE-2021-AVST4%20%26%20CVE-2021-AVST5Exploit · Third Party Advisory
→
https://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0Vendor Advisory

Quick Facts

CVE IDCVE-2021-45336
CVSS Score8.8 / 10
SeverityHIGH
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedDec 27, 2021

Related CVEs (NVD-CWE-noinfo)

CVE-2008-4615
10.0
CVE-2008-4630
10.0
CVE-2008-4595
10.0
CVE-2008-4594
10.0
CVE-2008-6021
10.0
CVE-2008-4690
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-45336 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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