{"type":"analysis","id":"analysis:research-backdoored-claude-code-extension-came-from-cursor-s-own-marketplace-not-open-vsx","slug":"research-backdoored-claude-code-extension-came-from-cursor-s-own-marketplace-not-open-vsx","title":"Backdoored Claude Code extension came from Cursor's own marketplace, not Open VSX","description":"Cursor confirms tampered Claude Code 2.1.312 and 2.1.313 builds on its marketplace for about 11 hours on Oct 29, reaching at most 5,000 users; registry checks find no Open VSX or npm release.","published_at":"2026-11-10T16:00:00.000Z","updated_at":"2026-11-10T16:00:00.000Z","record_date":"2026-11-10","topics":["cursor","anthropic","claude","research"],"source_urls":["https://cursor.com/blog/claude-code-extension-security-notice","https://phorion.io/blog/offical-claude-code-vsx-compromise","https://thehackernews.com/2026/10/official-claude-code-vs-code-extension.html","https://www.socket.dev/blog/claude-code-extension-compromise","https://www.stepsecurity.io/blog/claude-code-extension-trojanized"],"language":"en","routes":{"html":"https://newruntime.com/analysis/research-backdoored-claude-code-extension-came-from-cursor-s-own-marketplace-not-open-vsx/","markdown":"https://newruntime.com/analysis/research-backdoored-claude-code-extension-came-from-cursor-s-own-marketplace-not-open-vsx.md","json":"https://newruntime.com/analysis/research-backdoored-claude-code-extension-came-from-cursor-s-own-marketplace-not-open-vsx.json"},"author":{"role":"author","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"]},"editorial_provenance":{"desk":"authorial","target_ref":"deep_research:daf67b15-b0e2-4423-9c46-0ac10a4362f8","authorial_article_id":"daf67b15-b0e2-4423-9c46-0ac10a4362f8"},"next_reads":[{"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":"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":"collection","path":"/analysis/","url":"https://newruntime.com/analysis/","title":"Analysis","reason":"Open the latest authorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/analysis.json"},{"type":"collection","path":"/sources/","url":"https://newruntime.com/sources/","title":"Sources","reason":"See the original sources this archive cites.","media_type":"text/html"}]}