What is CVE-2021-42705?

CVE-2021-42705 is a high-severity vulnerability in We-Con Plc Editor, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2021-11-22.

How severe is CVE-2021-42705?

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

Buffer overflow in We-Con Plc Editor

CVE-2021-42705

PLC Editor Versions 1.3.8 and prior is 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 2021-11-22 · 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: 0.010 (62.5th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 62.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: +0.001

Affected products

We-Con Plc Editor
Wecon Plc Editor — versions All

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

us-cert.cisa.gov/ics/advisories/icsa-21-315-01 (US Government Resource, Third Party Advisory)

Frequently asked questions

What is CVE-2021-42705?: CVE-2021-42705 is a high-severity vulnerability in We-Con Plc Editor, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2021-11-22.
How severe is CVE-2021-42705?: High severity. CVSS v3 base score is 7.8 out of 10.