AI agent incident

Plugin4Shell let plugin repository owners swap pinned code in four coding agents

Reported · 1 source

What happened

Air Security disclosed a flaw it called Plugin4Shell that lets the owner of a plugin repository replace pinned plugin code with malicious code in Claude Code, Codex, GitHub Copilot and the Gemini CLI from Google. Anthropic and OpenAI had fixed it at the time of the report, and GitHub Copilot reportedly had not.

Why it matters

Version pinning is the control most teams assume protects them from a plugin author turning hostile. Here the pin pointed at content the author could still change underneath it.

Sources

  1. The Hacker News Plugin4Shell Lets Repository Owners Swap Pinned Plugin Code Across Four AI Coding Agents

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Background reading

Agent plugins and skills are a supply chain An explainer on the problem behind this incident.

Cite or correct this record

“Plugin4Shell let plugin repository owners swap pinned code in four coding agents.” The Permission Layer AI Agent Incident Database, https://thepermissionlayer.com/incidents/plugin4shell-pinned-plugin-swap/. Database updated October 22, 2026.

Every record traces to the dated sources above. If something here is wrong or missing, email [email protected] and it gets fixed. See this record in the full list.

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