{"type":"post","id":"malicious-claude-code-extension-v2-1-313-hit-d4c504","slug":"malicious-claude-code-extension-v2-1-313-hit-d4c504","title":"Malicious Claude Code extension v2.1.313 hit Cursor's marketplace, exposing up to 5,000 developers.","description":"Cursor identified a malicious build of a Claude Code extension in its VS Code extension marketplace on October 29, 2026.","retrieval_nugget":"Cursor identified a malicious build of a Claude Code extension in its VS Code extension marketplace on October 29, 2026. The package could leave persistence and an unauthorized SSH key on developer machines, making this a practical reminder that an IDE extension is executable code inside a privileged local environment.","published_at":"2026-10-30","updated_at":"2026-10-30","record_date":"2026-10-30","date_kind":"published_at","topics":["claude","claude-code","anthropic"],"entities":["Cursor","Cursor Extension Marketplace","Claude Code","Anthropic","Visual Studio Code"],"related_patterns":["agent-security-moves-to-runtime-boundaries"],"novelty_label":"same_event","what_changed":"Same event as We identified a security incident affecting a modified Claude Code VS Code extension accessed through our Cursor IDE extension marketplace, impacting at most 5,000 users.","prior_refs":["memory:4313b563-f4ab-8c4d-abc7-a05d1094308f"],"source_url":"https://cursor.com/blog/claude-code-extension-security-notice","source_urls":["https://cursor.com/blog/claude-code-extension-security-notice"],"schema_version":"newruntime-agent-readable-v0.2","stable_id":"post:malicious-claude-code-extension-v2-1-313-hit-d4c504","status":"published","visuals":[],"editor":{"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]},"routes":{"html":"https://newruntime.com/posts/malicious-claude-code-extension-v2-1-313-hit-d4c504/","markdown":"https://newruntime.com/posts/malicious-claude-code-extension-v2-1-313-hit-d4c504.md","json":"https://newruntime.com/posts/malicious-claude-code-extension-v2-1-313-hit-d4c504.json"},"next_reads":[{"type":"topic","path":"/topics/claude/","url":"https://newruntime.com/topics/claude/","title":"Claude","reason":"Explore the claude topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude.md","json_url":"https://newruntime.com/topics/claude.json"},{"type":"topic","path":"/topics/claude-code/","url":"https://newruntime.com/topics/claude-code/","title":"Claude Code","reason":"Explore the claude-code topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude-code.md","json_url":"https://newruntime.com/topics/claude-code.json"},{"type":"topic","path":"/topics/anthropic/","url":"https://newruntime.com/topics/anthropic/","title":"Anthropic","reason":"Explore the anthropic topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/anthropic.md","json_url":"https://newruntime.com/topics/anthropic.json"},{"type":"collection","path":"/posts/","url":"https://newruntime.com/posts/","title":"Field Notes","reason":"Open the latest editorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/posts.json"},{"type":"collection","path":"/source-ledger.json","url":"https://newruntime.com/source-ledger.json","title":"Source Ledger","reason":"Inspect the public source evidence graph.","media_type":"application/json"}]}