ChromeOS M-139, version 16328.55.0, has been released to the Stable channel. Users encountering new issues are encouraged to file bugs or utilize ChromeOS communities for reporting. Feedback can also be submitted directly through Chrome. The update includes several significant security fixes. A high-severity Use After Free vulnerability in the Arm Ltd Bifrost GPU Userspace Driver is addressed. Another medium-severity Use After Free vulnerability affecting the Linux system as a local user has been patched. Several Chrome Browser security fixes are also part of this release. These include high-severity issues like a race condition in V8 and a heap buffer overflow in libaom. Medium-severity fixes involve use-after-free vulnerabilities in Cast and Extensions, along with an inappropriate implementation in the File Picker. Lower-severity fixes address issues in Extensions, Filesystems, Permissions, and DOM input validation. Detailed information on Android security fixes is available separately.