#gemini-cli

September 18, 2026

Plugin4Shell is a plugin SHA-pinning bypass that yields zero-click RCE in Claude Code, Codex, GitHub Copilot, and Gemini CLI: the agent checks out the commit the marketplace pinned but never verifies the checkout actually resolved to it, so whoever controls the plugin repo can serve malicious code while the pin still looks honored. Air Security's lab has a working PoC against all four agents, says Microsoft has not shipped a Copilot fix, and reports Google will not fix Gemini CLI because it is deprecated; plugins inherit the operator's full permissions, so no privilege escalation is needed (Air Security, The Register). The same lab's earlier work claims 26,000 agents seized via a planted skill and 925 in-use skills hijacked affecting 134,000 agents. SahAssar strips it to the core: control the repo, set the default branch state to a matching SHA, and you get RCE on anyone who installs — "pretty bad for a package manager" (discussion). · AI & Agent Security