What is CVE-2021-43556?

CVE-2021-43556 is a high-severity vulnerability in Fatek Winproladder, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2021-12-28.

How severe is CVE-2021-43556?

High severity. CVSS v3 base score is 7.8 out of 10.

Buffer overflow in Fatek Winproladder

CVE-2021-43556

FATEK WinProladder Versions 3.30_24518 and prior are vulnerable to a stack-based buffer overflow while processing project files, which may allow an attacker to execute arbitrary code.

Vulnerability class: Buffer Overflow

Published 2021-12-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.021 (80.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 80.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.021 · newest: 0.021 · change: 0.000

Affected products

Fatek Winproladder
Fatek Automation Winproladder — versions All

Weakness classification (CWE)

References

us-cert.cisa.gov/ics/advisories/icsa-21-320-01 (US Government Resource, Third Party Advisory, Mitigation)
www.zerodayinitiative.com/advisories/ZDI-22-029/ (VDB Entry, Third Party Advisory)
www.zerodayinitiative.com/advisories/ZDI-22-032/ (VDB Entry, Third Party Advisory)
www.zerodayinitiative.com/advisories/ZDI-22-031/ (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43556?: CVE-2021-43556 is a high-severity vulnerability in Fatek Winproladder, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2021-12-28.
How severe is CVE-2021-43556?: High severity. CVSS v3 base score is 7.8 out of 10.