"Urgent Fix Needed: Critical Bootloader Vulnerability Threatens Linux Distros"
A critical vulnerability in the Shim Linux bootloader, CVE-2023-40547, allows attackers to execute code and take control of a system before the kernel loads, bypassing security mechanisms. The flaw, discovered by Microsoft's security researcher Bill Demirkapi, resides in Shim's parsing of HTTP responses, enabling an out-of-bounds write. Linux distributions using Shim, such as Red Hat, Debian, Ubuntu, and SUSE, have released advisories and patches. Users are advised to update to Shim v15.8, which contains a fix for CVE-2023-40547, and update the UEFI Secure Boot DBX to include the vulnerable Shim software's hashes and sign the patched version with a valid Microsoft key.