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AntivirusApplication · Avast

CVE-2025-3500

CRITICAL · 9.8 CVSS v3.1 Published 2025-12-01
Fix available
A fix is available. Upgrade to 25.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
Integer Overflow or Wraparound vulnerability in Avast Antivirus (25.1.981.6) on Windows allows Privilege Escalation.This issue affects Antivirus: from 25.1.981.6 before 25.3.

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 · moderate confidence

An integer overflow or wraparound vulnerability exists in Avast Antivirus versions 25.1.981.6 through versions prior to 25.3 on Windows. The vulnerability allows privilege escalation, likely due to improper integer handling in the antivirus driver or related component that could be exploited to gain elevated system privileges.

MitigationUpdate Avast Antivirus to version 25.3 or later to remediate this vulnerability. Organizations should prioritize patching given the critical CVSS score of 9.8 and the privilege escalation capability.

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
AntivirusApplication
Affected:>= 25.1.981.6, < 25.3

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Verify Avast Antivirus is installed
    Open Control Panel > Programs and Features, or run 'Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*Avast*"}' in PowerShell
    Affected if Avast Antivirus is listed in installed programs
  2. Determine installed Avast version
    Right-click the Avast icon in the system tray and select 'About Avast', or open Avast > Menu > Settings > About, or run 'avp.exe version' from the Avast installation directory
    Affected if A version number is displayed in the format XX.X.XXXX.XX or similar
  3. Compare version against affected range
    Check if the installed version is >= 25.1.981.6 AND < 25.3. Note that version 25.3 and later are NOT affected.
    Affected if Installed version is 25.1.981.6 through any 25.2.x.x version (any version starting with 25.2, or 25.1.981.6 exactly, but NOT 25.3 or higher)
  4. Confirm Avast service or driver is active
    Open Services.msc and look for 'Avast Antivirus' service status, or run 'sc query avast' or 'Get-Service -Name "Avast*"' in PowerShell
    Affected if The Avast Antivirus service is running (the vulnerability exists in the driver/component, so it requires the product to be active)

You are affected if Avast Antivirus version 25.1.981.6 through any 25.2.x.x version is installed and the Avast service/driver is active on a Windows system.

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.

dbcve · scoped
Upgrade available Upgrade to 25.3 or later
Fixed in 25.3
Interim mitigation

Update Avast Antivirus to version 25.3 or later to remediate this vulnerability. Organizations should prioritize patching given the critical CVSS score of 9.8 and the privilege escalation capability.

Recommended fix Moderate confidence

25.3

  1. Open the Avast Antivirus application on your Windows system
  2. Navigate to the update section (typically found in Settings > General > Update or via the Menu option)
  3. Click 'Check for updates' to download the latest version
  4. Ensure the update completes to version 25.3 or later
  5. Restart your computer if prompted to complete the installation
  6. Verify the installed version is 25.3 or higher by checking About in the application

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Antivirus Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

Scan for this in your stack

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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-2025-3500 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