CVE-2020-20118Public exploit

System crash via unchecked driver IOCTL write

Published Jul 11, 2023 · Updated Jul 9, 2026

Buffer overflow in Avast AntiVirus before 19.7 allows local users to cause a system crash through a crafted aswSnx.sys request. IOCTL 0x82AC0060 in aswSnx.sys fails to validate request bounds before writing outside the intended buffer. Low-privileged local access is required, and the demonstrated consequence is a system crash rather than data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Avast AntiVirus before 19.7 allows local users to cause a system crash through a crafted aswSnx.sys request. IOCTL 0x82AC0060 in aswSnx.sys fails to validate request bounds before writing outside the intended buffer. Low-privileged local access is required, and the demonstrated consequence is a system crash rather than data disclosure or modification.

The record

CVE
CVE-2020-20118
Published
Jul 11, 2023
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

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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