What is CVE-2021-43000?

CVE-2021-43000 is a high-severity vulnerability in Amzetta Zportal Windows Zclient, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.8/10. Published 2021-12-07.

How severe is CVE-2021-43000?

High severity. CVSS v3 base score is 8.8 out of 10.

Buffer overflow in Amzetta Zportal Windows Zclient

CVE-2021-43000

Amzetta zPortal Windows zClient is affected by Buffer Overflow. IOCTL Handler 0x22001B in the Amzetta zPortal Windows zClient <= v3.2.8180.148 allow local attackers to execute arbitrary code in kernel mode or cause a denial of service (memory corruption and OS crash) via specially crafted I/O Request Packet.

Vulnerability class: Buffer Overflow

Published 2021-12-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (37.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 37.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Amzetta Zportal Windows Zclient

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

www.sentinelone.com/labs/usb-over-ethernet-multiple-privilege-escalation-vulner… (Technical Description, Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43000?: CVE-2021-43000 is a high-severity vulnerability in Amzetta Zportal Windows Zclient, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.8/10. Published 2021-12-07.
How severe is CVE-2021-43000?: High severity. CVSS v3 base score is 8.8 out of 10.