A privilege-escalation vulnerability was discovered in the Linux kernel built with User Namespace (CONFIG_USER_NS) support. The flaw occurred when the ptrace() system call was used on a root-owned process to enter a user namespace. A privileged namespace user could exploit this flaw to potentially escalate their privileges on the system, outside the original namespace.
Linux kernel built with the User Namespaces(CONFIG_USER_NS) support is
vulnerable to a potential privilege escalation flaw. It could occur when a
root owned process tries to enter a user namespace, wherein a user attempts
to attach the entering process via ptrace(1).
A privileged name space user could use this flaw to potentially escalate their
privileges on the system.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1295288]
This issue does not affect the versions of the kernel package as shipped with
Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.
kernel-4.3.3-300.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
kernel-4.3.4-200.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.