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Avg AntivirusApplication · Avast

CVE-2020-13657

MEDIUM · 5.5 CVSS v3.1 Published 2020-06-29
Fix available
A fix is available. Upgrade to 20.4 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An elevation of privilege vulnerability exists in Avast Free Antivirus and AVG AntiVirus Free before 20.4 due to improperly handling hard links. The vulnerability allows local users to take control of arbitrary files.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a local privilege escalation vulnerability in Avast Free Antivirus and AVG AntiVirus Free versions before 20.4. The software improperly handles hard links, allowing a local attacker to take control of arbitrary files on the system and potentially escalate privileges.

MitigationUpdate Avast Free Antivirus or AVG AntiVirus Free to version 20.4 or later to remediate this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Avg AntivirusApplication
Affected:< 20.4
Free AntivirusApplication
Affected:< 20.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Avast Free Antivirus version
    Open Avast user interface, go to Menu > Settings > About, or right-click the Avast icon in system tray and select 'About Avast' to view the installed version number
    Affected if The displayed version is below 20.4 (for example, 20.3.x, 20.2.x, or earlier)
  2. Check AVG AntiVirus Free version
    Open AVG user interface, go to Menu > Settings > About, or right-click the AVG icon in system tray and select 'About AVG' to view the installed version number
    Affected if The displayed version is below 20.4 (for example, 20.3.x, 20.2.x, or earlier)
  3. Check version via Windows Programs and Features
    Open Control Panel > Programs and Features, find 'Avast Free Antivirus' or 'AVG AntiVirus Free' in the list, and note the version shown in the 'Version' column
    Affected if The version listed is below 20.4
  4. Check version via command line
    Open Command Prompt and run: wmic product where "name like 'Avast%%' or name like 'AVG%%'" get name,version
    Affected if The version output shows a number lower than 20.4

If any installed version of Avast Free Antivirus or AVG AntiVirus Free is found to be below 20.4, the system is affected by this hard link privilege escalation vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 20.4 or later
Fixed in 20.4
Interim mitigation

Update Avast Free Antivirus or AVG AntiVirus Free to version 20.4 or later to remediate this vulnerability.

Fix this in Avg Antivirus Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-13657 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data