Security readout for executives and security teams
Plain-English summary
CVE-2021-42705 affects WECON PLC Editor, software used to work with PLC project files. A malicious project file could crash or take over the user’s workstation when opened. The risk is highest for engineering environments where project files are exchanged by email, downloads, vendors, or contractors.
Executive priority
Treat this as a high-priority engineering workstation risk, especially in industrial operations. It is not reported as actively exploited in the provided sources, but successful exploitation could compromise systems used to manage PLC projects.
Technical view
PLC Editor 1.3.8 and prior has a stack-based buffer overflow when processing project files. The CVSS vector is local, low complexity, no privileges required, and user interaction required, with high confidentiality, integrity, and availability impact. The provided sources do not name a specific fixed version.
Likely exposure
Engineering workstations or maintenance laptops with WECON PLC Editor 1.3.8 or earlier are the likely exposure point. The vulnerability is triggered through project-file handling, so exposure depends on who can supply files to users who operate the editor.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Exploitation would require a user to open a crafted project file locally, making phishing, vendor file exchange, or compromised project repositories plausible delivery paths.
Researcher notes
Evidence is limited to the CVE summary and CISA ICS advisory reference. The core issue is CWE-121 stack-based buffer overflow during project-file parsing. Avoid assuming network exploitability; the CVSS vector and description point to local execution with user interaction.
Mitigation direction
- Identify all WECON PLC Editor installations and versions.
- Check WECON and CISA advisory guidance for available updates or mitigations.
- Do not open PLC project files from untrusted or unexpected sources.
- Restrict editor use to controlled engineering workstations.
- Scan and quarantine externally received project files before use.
Validation and detection
- Confirm whether PLC Editor 1.3.8 or earlier is installed.
- Review how PLC project files enter the organization.
- Check endpoint telemetry for crashes tied to PLC Editor file opening.
- Verify users receive project files only through approved channels.
- Track vendor advisory status until a supported fix is confirmed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-42705 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://us-cert.cisa.gov/ics/advisories/icsa-21-315-01CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.