CVE-2026-7574 Details

A vulnerability exists in Anthropic Claude Desktop Cowork VM image handling, specifically in versions 1.1348.0 through 1.2278.0. The issue arises because the application only checks for the presence of the VM image file and a version marker string before booting the root filesystem image. It fails to verify the integrity of the image content at the time of use. This flaw allows a local attacker with unprivileged code execution as the victim macOS user to modify the VM root filesystem image, which is then trusted on subsequent Cowork VM boots. Exploitation of this vulnerability enables persistent arbitrary code execution within the VM and access to directories mounted from the host.

To address this vulnerability, it is recommended to implement a verification process that computes and checks the SHA256 hash of 'rootfs.img' before each boot, comparing it to an expected value. Additionally, integrating in-VM integrity enforcement measures, such as dm-verity or fs-verity, and making the root filesystem read-only at the virtualization framework layer while using an overlay for writes can enhance security. Using signed VM images and storing them in a macOS-protected location where unprivileged users cannot modify them are also advisable steps.