{"uuid": "5e57946e-2bb3-4bc8-af70-f01de315e247", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2025-59536", "type": "published-proof-of-concept", "source": "https://t.me/CyberSecurityExploit/29859", "content": "\ud83d\udee1 CVE-2026-21852-PoC (Educational Demo Repo)\n\ud83d\udce6 Repository: atiilla/CVE-2026-21852-PoC\n\ud83d\udc49 https://github.com/atiilla/CVE-2026-21852-PoC\n\nThis repository demonstrates historical PoC patterns for vulnerabilities in the Anthropic Claude Code CLI tool, including CVE-2026-21852, designed for educational purposes only.\n\n\ud83d\udccc What This Repo Contains\n\ud83d\udcc2 Demo directories for historical bugs\nExamples show how malicious config files can influence tool behavior\n\n\ud83d\udc0d Python scripts:\n\u2022 attacker_server.py \u2013 Local server to capture and log simulated traffic\n\u2022 attacker_proxy.py \u2013 Proxy for observing exfiltration behavior\n\u2022 scanner.py \u2013 Scanner to detect risky patterns in local repositories\n\n\ud83d\udcc1 Demo content directories include:\n\u2022 vuln1_hooks_bypass/\n\u2022 CVE-2025-59536_mcp_injection/\n\u2022 CVE-2026-21852_api_exfil/\n(Configuration files under these folders illustrate pattern examples.)\n\n\ud83e\udde0 Vulnerabilities Covered\nThe project explores multiple vulnerabilities historically disclosed for Claude Code CLI:\n\u26a0\ufe0f Hooks consent bypass \u2013 bypasses consent mechanisms (older build)\n\u26a0\ufe0f CVE-2025-59536 \u2013 MCP config injection \u2013 orchestration config risk\n\u26a0\ufe0f CVE-2026-21852 \u2013 API key disclosure \u2013 config causes API key to be sent before trust verification\nThe vulnerability CVE-2026-21852 identified that malicious repository settings could exfiltrate API keys prior to showing a trust prompt in affected Claude Code versions.\n\n\ud83c\udfaf How the Repo Can Be Used (Education Only)\n\ud83d\udccc Scanner\npython3 scanner.py \nDetects dangerous config patterns that could be risky before opening repositories.\n\n\ud83d\udccc Local Demo Server\npython3 attacker_server.py\nSimulates a server to log simulated exfiltration traffic.\n\n\ud83d\udccc Proxy Demo\npython3 attacker_proxy.py\nTransparent proxy to illustrate capture behavior.\n\n\ud83e\udde0 What You Learn Here\n\u2714\ufe0f How untrusted configuration files can impact tool behavior\n\u2714\ufe0f Why verifying repository contents before opening is important\n\u2714\ufe0f The concept of pre-execution key leakage (API exfiltration)\n\u2714\ufe0f How scanners can detect repository risk patterns\nThese skills are valuable in secure dev workflows, supply chain security, and blue team defensive validation.\n\n\u26a0\ufe0f Important Notes (Responsible Use)\n\u2705 This repository is for security research and learning only.\n\u274c Do NOT deploy these scripts against third-party or production systems.\n\u274c Never open untrusted repositories in real tools without inspection.\n\u2696\ufe0f Always practice ethical/authorized testing and use isolated lab environments.\n\n\ud83d\udccc Additional Reference: CVE-2026-21852 Description\n\ud83d\udccc The vulnerability CVE-2026-21852 pertains to an information disclosure issue in Claude Code \n       where repository settings could cause premature API calls before trust confirmation, risking API key exfiltration.\n\n\u2796\u2796\u2796\u2796\u2796\u2796\u2796\u2796\u2796\u2796\n\n\ud83d\udd10 Cyber Security Exploit Community\nTelegram Group\nhttps://t.me/Cyber_Security_Exploit\n\nTelegram Channel\nhttps://t.me/CyberSecurityExploit\n\nResearch \u2022 Ethical Hacking \u2022 Red Team", "creation_timestamp": "2026-08-16T00:00:23.926186Z"}