What is CVE-2021-42707?

CVE-2021-42707 is a high-severity vulnerability in We-Con Plc Editor, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2021-11-22.

How severe is CVE-2021-42707?

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

Buffer overflow in We-Con Plc Editor

CVE-2021-42707

PLC Editor Versions 1.3.8 and prior is vulnerable to an out-of-bounds write 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 (60.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.010 · change: +0.001

Affected products

We-Con Plc Editor
Wecon Plc Editor — versions All

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

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

Frequently asked questions

What is CVE-2021-42707?: CVE-2021-42707 is a high-severity vulnerability in We-Con Plc Editor, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2021-11-22.
How severe is CVE-2021-42707?: High severity. CVSS v3 base score is 7.8 out of 10.