How severe is CVE-2021-31727?

CVE-2021-31727 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-2021-31727 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31727?

CVE-2021-31727 affects Malwarefox Antimalware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-31727?

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-2021-31727 published?

CVE-2021-31727 was published on 2021-05-17 and last updated on 2026-06-17.

CVE-2021-31727

CVE-2021-31727 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

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Malwarefox Antimalware
Published: 2021-05-17
Last modified: 2026-06-17

Description

Incorrect access control in zam64.sys, zam32.sys in MalwareFox AntiMalware 2.74.0.150 where IOCTL's 0x80002014, 0x80002018 expose unrestricted disk read/write capabilities respectively. A non-privileged process can open a handle to \.\ZemanaAntiMalware, register with the driver using IOCTL 0x80002010 and send these IOCTL's to escalate privileges by overwriting the boot sector or overwriting critical code in the pagefile.

Frequently asked questions

What is CVE-2021-31727?: Incorrect access control in zam64.sys, zam32.sys in MalwareFox AntiMalware 2.74.0.150 where IOCTL's 0x80002014, 0x80002018 expose unrestricted disk read/write capabilities respectively. A non-privileged process can open a handle to \.\ZemanaAntiMalware, register with the driver using IOCTL 0x80002010 and send these IOCTL's to escalate privileges by overwriting the boot sector or overwriting critical code in the pagefile.
How severe is CVE-2021-31727?: CVE-2021-31727 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-2021-31727 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31727?: CVE-2021-31727 affects Malwarefox Antimalware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-31727?: 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-2021-31727 published?: CVE-2021-31727 was published on 2021-05-17 and last updated on 2026-06-17.

References

https://github.com/irql0/CVE-2021-31728/blob/master/CVE-2021-31727.md

Affected products (1)

cpe:2.3:a:malwarefox:antimalware:2.74.0.150:*:*:*:*:*:*:*

More vulnerabilities in Malwarefox Antimalware

CVE-2021-31728 — High (CVSS 7.8): Incorrect access control in zam64.sys, zam32.sys in MalwareFox AntiMalware 2.74.0.150 allows a non-privileged process…
CVE-2018-6606 — High (CVSS 7.8): An issue was discovered in MalwareFox AntiMalware 2.74.0.150. Improper access control in zam32.sys and zam64.sys allows…
CVE-2018-6593 — High (CVSS 7.8): An issue was discovered in MalwareFox AntiMalware 2.74.0.150. Improper access control in zam32.sys and zam64.sys allows…

All CVEs affecting Malwarefox Antimalware →