Virtualization | Breaking Cybersecurity News | The Hacker News

Cybersecurity researchers have uncovered a sandbox escape vulnerability in Anthropic's Claude Cowork that makes it possible to break out of the confines of a Linux virtual machine (VM) within which the agent runs to read or write files anywhere on the Mac. Accomplish AI, which shared details of the vulnerability with The Hacker News ahead of publication, said about 500,000 macOS users running local Cowork sessions were affected prior to it being patched. It has been codenamed SharedRoot . "We connected a folder to a fresh Claude Cowork session, sent one short message, and watched the agent escape the sandbox," Oren Yomtov, principal security researcher at Accomplish AI, said . "From inside the VM, it reached the host Mac and read and wrote files all over it, far outside the folder we'd connected, with no permission prompt anywhere." With this level of access, the agent can access any data stored on the Mac via the user's account, including SSH ke...

A use-after-free bug in Linux's KVM hypervisor can be triggered from a guest virtual machine to corrupt the shadow-page state of the host kernel that runs it. Dubbed ' Januscape ' and tracked as  CVE-2026-53359 , the flaw sits in the shadow MMU code that KVM shares across both Intel and AMD. The public proof-of-concept panics the host; the researcher claims that a separate, unreleased exploit turns the same bug into full host code execution. Security researcher  Hyunwoo Kim (@v4bel) found and reported the bug. He described Januscape as the first guest-to-host exploit triggerable on both Intel and AMD, to the best of public knowledge. The flaw went unnoticed for roughly 16 years. According to Kim, the exploit was used as a zero-day submission in  Google's kvmCTF , the controlled KVM vulnerability reward program that offers up to $250,000 for full guest-to-host escapes. How It Works To run a virtual machine, KVM keeps its own private set of page tables that mi...