CVE-2026-97938

/// Technical description

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

reboot: fix cad_pid use-after-free race

cad_pid is a single kernel-wide struct pid pointer. proc_do_cad_pid()

reads it and passes it to pid_vnr() without protecting the lifetime of

the referenced struct pid. A concurrent writer can replace cad_pid and

drop the final reference to the old struct pid after the reader has

loaded the pointer but before pid_vnr() has finished dereferencing it,

causing a use-after-free.

kill_cad_pid() has the same lifetime race when it passes cad_pid to

kill_pid().

At the time this issue was reported, an unprivileged user could reach the

sysctl through user and PID namespaces because cad_pid was registered in

pid_table[]. Moving cad_pid back to the global reboot sysctl table

corrected that namespace and permission mismatch, but did not fix the

underlying lifetime race.

Fix this by treating cad_pid as an RCU-protected pointer at both read

sites and by waiting for a grace period before dro

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References