CVE-2021-31728

CVE-2021-31728 is a high-severity vulnerability in Malwarefox Antimalware with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

Incorrect access control in zam64.sys, zam32.sys in MalwareFox AntiMalware 2.74.0.150 allows a non-privileged process to open a handle to \.\ZemanaAntiMalware, register itself with the driver by sending IOCTL 0x80002010, allocate executable memory using a flaw in IOCTL 0x80002040, install a hook with IOCTL 0x80002044 and execute the executable memory using this hook with IOCTL 0x80002014 or 0x80002018, this exposes ring 0 code execution in the context of the driver allowing the non-privileged process to elevate privileges.

Frequently asked questions

What is CVE-2021-31728?
Incorrect access control in zam64.sys, zam32.sys in MalwareFox AntiMalware 2.74.0.150 allows a non-privileged process to open a handle to \.\ZemanaAntiMalware, register itself with the driver by sending IOCTL 0x80002010, allocate executable memory using a flaw in IOCTL 0x80002040, install a hook with IOCTL 0x80002044 and execute the executable memory using this hook with IOCTL 0x80002014 or 0x80002018, this exposes ring 0 code execution in the context of the driver allowing the non-privileged process to elevate privileges.
How severe is CVE-2021-31728?
CVE-2021-31728 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-31728 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31728?
CVE-2021-31728 affects Malwarefox Antimalware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-31728?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-31728 published?
CVE-2021-31728 was published on 2021-05-17 and last updated on 2026-06-17.

References

Affected products (1)

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