CVE-2025-13032Public exploit

SYSTEM privilege escalation via double-fetched string length

Published Nov 11, 2025 · Updated Nov 11, 2025

A double fetch in Avast Antivirus and Avast One before 25.3 allows local users to gain SYSTEM privileges on Windows. The aswSnx handler for IOCTL 0x82AC0204 rereads a user-controlled UNICODE_STRING length, allocating a kernel pool buffer with one value and copying with another. Exploitation requires enrolling an attacker-controlled process in the Avast sandbox before racing the length change, and successful overflow grants SYSTEM-level control.

CVSS severity9.9
Critical
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A double fetch in Avast Antivirus and Avast One before 25.3 allows local users to gain SYSTEM privileges on Windows. The aswSnx handler for IOCTL 0x82AC0204 rereads a user-controlled UNICODE_STRING length, allocating a kernel pool buffer with one value and copying with another. Exploitation requires enrolling an attacker-controlled process in the Avast sandbox before racing the length change, and successful overflow grants SYSTEM-level control.

The record

CVE
CVE-2025-13032
Published
Nov 11, 2025
Updated
Nov 11, 2025
Vendor
Avast
Product
Avast One
Classifications
CWE-367, CAPEC-233, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 11, 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 <25.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Avast · Avast Oneversion=0 <25.3
Avast · Avast Antivirusversion=0 <25.3

Published CVSS scores

9.9Gen DigitalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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.

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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-367Time-of-check Time-of-use (TOCTOU) Race Condition
CAPEC-233Privilege Escalation
T1068Exploitation for Privilege Escalation

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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