CVE-2022-4291

Sandbox escape via cross-version double-free

Published Dec 7, 2022 · Updated Apr 14, 2025

Heap corruption in Gen Digital Avast Antivirus Script Shield 18.0.1473.0 and earlier allows local users to escape an application sandbox. A protocol mismatch between older main-process and newer child-process copies of aswJsFlt.dll causes the named-pipe server to free heap memory twice. Exploitation requires Windows, a sandboxed host application, and mixed DLL versions; successful exploitation escapes the sandbox, while failure crashes the host process.

CVSS severity7.7
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap corruption in Gen Digital Avast Antivirus Script Shield 18.0.1473.0 and earlier allows local users to escape an application sandbox. A protocol mismatch between older main-process and newer child-process copies of aswJsFlt.dll causes the named-pipe server to free heap memory twice. Exploitation requires Windows, a sandboxed host application, and mixed DLL versions; successful exploitation escapes the sandbox, while failure crashes the host process.

The record

CVE
CVE-2022-4291
Published
Dec 7, 2022
Updated
Apr 14, 2025
Vendor
Gen Digital
Product
Avast Antivirus
Classifications
CWE-119, T1203
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 7, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=18.0.1473.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Gen Digital · Avast Antivirusversion=0 <=18.0.1473.0

Published CVSS scores

7.7Gen DigitalCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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