CVE-2026-80929

A flaw was found in the Linux kernel. A non-root user can exploit a vulnerability in the sysctl mechanism, specifically related to the cad_pid entry. By unsharing process ID (PID) and user namespaces, a local attacker can modify this global system control from a child namespace. This allows a user without administrative privileges to alter a critical system setting that should only be modifiable by the root user, leading to privilege escalation.

A flaw of moderate impact was found in the Linux kernel sysctl mechanism. The cad_pid sysctl is a global setting used by the kernel's Ctrl-Alt-Del (reboot) handling, and should only be readable and modifiable by the global root user. However, because it was registered in pid_table[] and governed by pid_table_root_permissions(), a local unprivileged user could unshare PID and user namespaces and modify cad_pid from within the child namespace, altering a system control that should be restricted to the global root user and potentially enabling privilege escalation. Red Hat scored this flaw with a CVSS 3.1 score of 7.0 (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H), lower than the upstream NVD score of 7.8 primarily due to the higher attack complexity involved in exploiting the namespace-unsharing path. The vulnerable code was introduced in the upstream kernel 6.17 release, and none of the Red Hat Enterprise Linux or Red Hat OpenShift versions currently in support ship a kernel containing it: all current affects are marked not affected with the justification that the vulnerable code is not present. The Red Hat Enterprise Linux 6 Extended Lifecycle Support affect is out of support scope.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.