Atomic Stealer

Anthropic began contacting affected Claude users on August 30, 2026, after discovering that infostealer malware had compromised their computers and stolen active login session cookies, allowing attack…

Anthropic has begun locking users out of their Claude accounts after login sessions were hijacked by infostealer malware, including Vidar, Lumma (LummaC2), StealC, RedLine, Acreed on Windows, and Atom…