AI agent incident

SneakPeek let a file in a cloned repository steal secrets through Claude Code Desktop's preview pane

Reported · 2 sources

What happened

Noma Labs disclosed SneakPeek, three chained gaps in the preview pane of Claude Code Desktop. HTML files over 256KB loaded as file:// URLs without the content security policy applied to smaller files, and the request filter did not run for static files, so a padded coverage report in a public repository could run script and read local files as soon as a developer asked Claude to review it. Anthropic rated it CVSS 8.7, Noma bypassed the first patch with a Web Worker, and the full fix shipped on August 17 in Claude Desktop 1.30096.1.

Why it matters

The developer only asked the agent to look at a file. Rendering untrusted content runs with the user's file access, and each of the preview's three defenses had a gap. The files in reach included SSH keys, cloud and GitHub credentials and Claude's own OAuth tokens, so a coding agent's preview pane needs the same scrutiny as its shell.

Sources

  1. noma.security SneakPeek: How the Preview Pane in Claude Code Desktop Can Exfiltrate Your Data
  2. Dark Reading Anthropic 'SneakPeek' Flaw Is a Silent Zero-Click Threat

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Cite or correct this record

“SneakPeek let a file in a cloned repository steal secrets through Claude Code Desktop's preview pane.” The Permission Layer AI Agent Incident Database, https://thepermissionlayer.com/incidents/claude-code-desktop-sneakpeek/. 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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