Many MindedFake Claude Code add-on slipped into Cursor's extension store for eleven hours
A tampered copy of the Claude Code extension was listed in Cursor's VS Code extension marketplace on a Thursday and stayed available for roughly eleven hours. Cursor says up to 5,000 users could have been affected. Anthropic had no part in building the altered version.
The extension tried to collect each machine's hostname, username, operating system and public IP address. It also tried to set up remote access for the attacker. Cursor says that second step likely would have failed on most machines, because it needs admin privileges.
Once the problem was found, Cursor removed the extension and took the entire marketplace offline. It worked with providers to neutralize the malware, confirmed there was no further risk, and then restored the marketplace. Cursor states that no other extensions were affected.
This is a setback for the cheaper software creation that AI coding tools promise. Those tools lower the cost of building software, but they depend on extension stores that people install from without much checking. A convincing copy of a trusted name turns that convenience into an attack path, and developer machines are valuable targets. Each incident like this raises the verification burden on the people the tools are meant to empower.
The caveats are significant. Every detail here comes from Cursor's own statements, as relayed by The Decoder, with no independent verification. The 5,000 figure is an upper bound, not a confirmed count of infections. The remote-access assessment is a judgment ("likely"), not a tested result. The report does not say who the attacker was or how the extension was tampered with. Those are the points to watch.
Source: The Decoder