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title: AI Strikes Back: Using an LLM to write COBOL | daily.dev
description: A developer used GitHub Copilot to build a browser-based COBOL IDE with zero prior COBOL experience, and it worked impressively well. However, reading the...
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# AI Strikes Back: Using an LLM to write COBOL

**[marmelab](https://daily.dev/sources/Marmelab)** · 7 min read · 18 upvotes · 1 comments

## Summary

A developer used GitHub Copilot to build a browser-based COBOL IDE with zero prior COBOL experience, and it worked impressively well. However, reading the generated code revealed a critical remote code execution vulnerability: user-submitted COBOL was compiled and run directly on the server with no sandboxing. Copilot never flagged the security issue unprompted, but identified it clearly when explicitly asked. Three remediation approaches are discussed — Docker container isolation, syscall filtering, and compiling COBOL to WebAssembly for client-side execution. The key takeaway is that AI coding tools build what you describe, not what is safe to deploy; the judgment to ask the right security questions still requires a developer in the loop.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://marmelab.com/blog/2026/04/08/cobol-ai-strikes-back.html>

## Community discussion

Top comments from developers on daily.dev.

**@lucas39** · 0 upvotes

> COBOL is still used today in critical businesses, mainly for its reliability rather than its practicality or development speed, so it makes no sense to incorporate AI into the development cycle. It’s complete nonsense.

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---

Tags: [#github](https://daily.dev/tags/github), [#webassembly](https://daily.dev/tags/webassembly), [#ai-coding](https://daily.dev/tags/ai-coding)

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