ConfirmedVerifiedRating 5/5
At least one checkable detail was matched against the full text of the cited source.
Fact check
Cursor said the malicious version affected at most 5,000 users.
Appears in
- https://arstechnica.com/security/2026/10/anthropic-vs-code-extension-on-cursor-backdoored-for-nearly-12-hours
- https://www.wired.com/story/trojan-malware-targets-thousands-of-anthropic-claude-developer-systems
Verification ledger
- Checked by
- verification engine
- Atom checks
- 3/3
Other claims in this story
- ConfirmedVersion 2.1.313 of Anthropic's Claude VS Code extension, distributed through Anthropic's official account on Cursor's marketplace, was malicious.
- ConfirmedUsers who installed or updated the extension from Cursor between 5:27 am and 4:35 pm ET on Thursday are considered affected.
- ConfirmedPer Cursor, the malicious code attempted to add an attacker-controlled SSH key, enable the local SSH service, and open a reverse SSH tunnel.
- ConfirmedPer Cursor, bugs in the malicious code made the SSH-key step fail unless Cursor was started with administrator privileges.
- ConfirmedAnthropic released version 2.1.314 several hours after the malicious version appeared, per researcher Kevin Beaumont.
- ConfirmedAs of Ars Technica's report, Anthropic had not publicly warned customers about the incident.
- UnconfirmedThe attacker's collection of environment-variable names was used to prioritize machines holding cloud credentials for follow-up attacks.
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