HOMEVULNERABILITIESCVE-2021-45338
HIGH

CVE-2021-45338

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

7.8
CVSS v3.1

Official Description

Multiple privilege escalation vulnerabilities in Avast Antivirus prior to 20.4 allow a local user to gain elevated privileges by calling unnecessarily powerful internal methods of the main antivirus service which could lead to the (1) arbitrary file delete, (2) write and (3) reset security.

NVD Source

Technical Analysis

CVE-2021-45338 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 7.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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-AVST1.1
ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.2
ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.3
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-AVST1.1
ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.2
ADVISORYhttps://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.3
ADVISORYhttps://www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0

All References (8)

→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.1Exploit · Third Party Advisory
→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.2Exploit · Third Party Advisory
→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.3Exploit · 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-AVST1.1Exploit · Third Party Advisory
→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.2Exploit · Third Party Advisory
→
https://github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST1.3Exploit · 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-2021-45338
CVSS Score7.8 / 10
SeverityHIGH
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedDec 27, 2021

Related CVEs (NVD-CWE-Other)

CVE-2009-1358
10.0
CVE-2008-5404
10.0
CVE-2008-4237
10.0
CVE-2008-5415
10.0
CVE-2022-25226
10.0
CVE-2009-2296
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-45338 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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