CVE-2021-45337Public exploit

Protected-process elevation via wsc_proxy.exe hollowing

Published Dec 27, 2021 · Updated Aug 4, 2024

Privilege escalation in Avast Antivirus before 20.8 allows local users with SYSTEM privileges to run attacker code with AM-PPL protection. The Self-Defense driver marks a SYSTEM-launched wsc_proxy.exe process as antimalware PPL based on its image path while its creator retains an all-access handle, allowing the suspended process image to be overwritten before execution. Exploitation requires existing SYSTEM execution and grants protected-process status that can interfere with other antimalware-protected processes.

CVSS severity8.8
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Avast Antivirus before 20.8 allows local users with SYSTEM privileges to run attacker code with AM-PPL protection. The Self-Defense driver marks a SYSTEM-launched wsc_proxy.exe process as antimalware PPL based on its image path while its creator retains an all-access handle, allowing the suspended process image to be overwritten before execution. Exploitation requires existing SYSTEM execution and grants protected-process status that can interfere with other antimalware-protected processes.

The record

CVE
CVE-2021-45337
Published
Dec 27, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1055.012
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1055.012Process Injection: Process Hollowing

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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