CVE-2025-38499

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns<br /> <br /> What we want is to verify there is that clone won&amp;#39;t expose something<br /> hidden by a mount we wouldn&amp;#39;t be able to undo. "Wouldn&amp;#39;t be able to undo"<br /> may be a result of MNT_LOCKED on a child, but it may also come from<br /> lacking admin rights in the userns of the namespace mount belongs to.<br /> <br /> clone_private_mnt() checks the former, but not the latter.<br /> <br /> There&amp;#39;s a number of rather confusing CAP_SYS_ADMIN checks in various<br /> userns during the mount, especially with the new mount API; they serve<br /> different purposes and in case of clone_private_mnt() they usually,<br /> but not always end up covering the missing check mentioned above.