CVE-2021-31728Known exploitationPublic exploit

Local kernel code execution via driver IOCTLs

Published May 17, 2021 · Updated Aug 3, 2024

Incorrect access control in MalwareFox AntiMalware 2.74.0.150 allows local users to elevate privileges via malicious driver IOCTL requests. The zam64.sys and zam32.sys drivers accept unprivileged handle opens and IOCTLs that register a process, allocate executable memory, install a hook, and execute that memory in ring 0. Local users need only a non-privileged process with access to the driver device; successful exploitation yields kernel-level code execution and privilege elevation.

CVSS severity7.8
High
EPSS probability3.40%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect access control in MalwareFox AntiMalware 2.74.0.150 allows local users to elevate privileges via malicious driver IOCTL requests. The zam64.sys and zam32.sys drivers accept unprivileged handle opens and IOCTLs that register a process, allocate executable memory, install a hook, and execute that memory in ring 0. Local users need only a non-privileged process with access to the driver device; successful exploitation yields kernel-level code execution and privilege elevation.

The record

CVE
CVE-2021-31728
Published
May 17, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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