Shown·Partial·Claude Code
Reverse engineering a papercut zero-day
Claude Code analyzed a patch for an actively exploited Papercut NG vulnerability and worked to build a working exploit chain.
Within 90 minutes Claude produced a functional proof of concept confirming an authentication bypass across four tested endpoints.
Overview
How it was set up
Claude Code with Opus running in a code-server harness with custom skills for binary analysis, reporting, Proxmox lab deployment, Ghidra, semgrep, and Playwright MCP for installing the target app.
Worth knowing
A safety guardrail briefly blocked log analysis and swapped the model; the author notes the full exploit chain claim was not entirely accurate.
A prompt to start from
A new vulnerability was reported for [software]. Investigate whether a patch exists, build a lab for the vulnerable version, and diff the patch against available reports and indicators of compromise to find the root cause.Written by Agentic Feats from the source. Not the author's exact prompt.
Sources 1
History
- Source published
- 2026-08-30
- Added to Agentic Feats
- 2026-10-13
- Pick
- No
- Markdown copy
- /c/reverse-engineering-a-papercut-zero-day-claude-code.md
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