CVE-2025-3500

Kernel code execution via undersized buffer allocation

Published Dec 1, 2025 · Updated Feb 26, 2026

Integer overflow in Avast Antivirus 25.1.981.6 and later before 25.3 allows local users to execute code with kernel privileges. The aswbidsdriver kernel driver fails to validate user-supplied data before an overflowing integer calculation determines a buffer allocation. Exploitation requires prior low-privileged code execution on Windows and yields arbitrary code execution in the kernel context.

CVSS severity9.8
Critical
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in Avast Antivirus 25.1.981.6 and later before 25.3 allows local users to execute code with kernel privileges. The aswbidsdriver kernel driver fails to validate user-supplied data before an overflowing integer calculation determines a buffer allocation. Exploitation requires prior low-privileged code execution on Windows and yields arbitrary code execution in the kernel context.

The record

CVE
CVE-2025-3500
Published
Dec 1, 2025
Updated
Feb 26, 2026
Vendor
Avast
Product
Avast Antivirus
Classifications
CWE-190, CAPEC-233, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 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?

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

  1. Affected versionversion=25.1.981.6 <25.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Avast · Avast Antivirusversion=25.1.981.6 <25.3

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.0NortonLifeLock Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
8.8Trend Micro Zero Day InitiativeCVSS:3.0/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
CAPEC-233Privilege Escalation
T1068Exploitation for Privilege Escalation

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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