CVE-2021-42705

Code execution via unchecked WCP field length

Published Nov 22, 2021 · Updated Sep 16, 2024

Stack-based buffer overflow in WECON PLC Editor 1.3.8 and earlier allows remote attackers to execute code via crafted WCP files. The WCP parser copies user-supplied data into a stack buffer without validating its length, allowing memory corruption in the current process. Exploitation requires the target to open a malicious file or visit a malicious page, and successful code runs with the application's privileges.

CVSS severity7.8
High
EPSS probability1.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in WECON PLC Editor 1.3.8 and earlier allows remote attackers to execute code via crafted WCP files. The WCP parser copies user-supplied data into a stack buffer without validating its length, allowing memory corruption in the current process. Exploitation requires the target to open a malicious file or visit a malicious page, and successful code runs with the application's privileges.

The record

CVE
CVE-2021-42705
Published
Nov 22, 2021
Updated
Sep 16, 2024
Vendor
WECON Technology Co., Ltd.
Product
PLC Editor
Classifications
CWE-121, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=All <=1.3.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

WECON Technology Co., Ltd. · PLC Editorversion=All <=1.3.8

Published CVSS scores

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8ICS-CERTCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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