GHSA-q77q-crp2-mmjc: 
Python vulnerability analysis and mitigation

Summary

An Inefficient Regular Expression Complexity ('Catastrophic Backtracking / ReDoS', CWE-1333) vulnerability in LLM Markdown code-block and JSON extraction regexes (r"```(?:json)?\s*([\s\S]+?)+\s*```") allows remote attackers to freeze the Python/Node.js event loop (100% CPU Denial of Service) by returning a crafted unclosed code fence of 5,000 characters.

Proof of Concept (PoC)

import re
VULN_RE = re.compile(r"```(?:json)?\s*([a-zA-Z0-9_\s]+)+\s*```")
VULN_RE.search("```json\n" + "a" * 5000 + "!")

Remediation

Replace nested quantifier regular expressions with bounded linear-time string slicing (str.find()) and enforce a maximum input length limit.