CVE-2026-48986 pam_usb: Infinite loop DoS in process-tree walk when parent process exits during authentication

pamusb provides hardware authentication for Linux using removable media. In pamusb 0.9.1 and earlier, usbgetprocessparentid can cause an infinite loop DoS because it does not initialize ppid on failure. In pusblocallogin, the same variable is reused as input and output in a process-tree while loo...