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TI-2021-20489 Aliases CVE-2021-45338GHSA-9v35-rf4g-xvc2

Multiple privilege escalation vulnerabilities in Avast Antivirus prior to 20.4 allow a…

Priority LOW 34Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

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.

Why it matters now

EPSS 0.00393 33rd percentileScored 2026-11-07
Public exploit Yes 3 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:avast:antivirus:*:*:*:*:*:*:*:*before 20.4VulnerableAvast
  • cpe:2.3:a:avast:antivirus:*:*:*:*:*:*:*:* Versions before 20.4 Vulnerable ·Avast

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-45338
  2. 2026-10-03 Alias added: GHSA-9v35-rf4g-xvc2

References

Exploit 3

Advisory 1

  • TI-2020-08753 An issue was discovered in Avast Antivirus before 20. CVSS 3.1CRITICAL 9.8
  • TI-2017-05872 In Avast Antivirus before v17, using the LPC interface API exposed by the AvastSVC.exe… CVSS 3.0CRITICAL 9.8
  • TI-2025-03074 Integer Overflow in Avast Antiviurs 25.1.981.6 on Windows may result in privilege escalation CVSS 3.1CRITICAL 9.8
  • TI-2025-11929 Time-of-check time-of-use race condition in Avast Antivirus CVSS 3.1CRITICAL 9.9
  • TI-2021-20488 Privilege escalation vulnerability in the Self-Defense driver of Avast Antivirus prior to… CVSS 3.1HIGH 8.8
  • TI-2021-20487 Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to… CVSS 3.1HIGH 8.8
See all 31 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences