CVE-2026-80929

Summary

In the Linux kernel, the following vulnerability has been resolved:

sysctl: move the "cad_pid" entry from pid_table[] to kern_reboot_table[]

cad_pid is global, and kill_cad_pid() is only used in the root namespace.

However, due to pid_table_root_permissions(), a non-root user can unshare pid/user namespaces and modify it from the child namespace. This makes no sense and is simply wrong.

Move it to kern_reboot_table[] where it logically belongs; this ensures that only GLOBAL_ROOT_UID can read/modify this sysctl.

Note that this patch doesn't preserve "#ifdef CONFIG_PROC_SYSCTL" around the "cad_pid"; CONFIG_PROC_SYSCTL selects CONFIG_SYSCTL, so it is always set when kern_reboot_table[] is compiled.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe054bcbe7e7af2baad3752f1a4916a7fffc0457e < e8527de7fea191fda704792a56081f9009aeec37affected
LinuxLinuxe054bcbe7e7af2baad3752f1a4916a7fffc0457e < a09bc4eaa67e1a72df3b6d0beb3afeef1e1fdfcdaffected
LinuxLinuxe054bcbe7e7af2baad3752f1a4916a7fffc0457e < 7170ca01623b399c97f2ae9d3e228badc1f25ea3affected
LinuxLinux6.17affected
LinuxLinux0 < 6.17unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References