CVE-2026-53075

A flaw was found in the Linux kernel's Point-to-Point Protocol (PPP) subsystem. A local unprivileged user can exploit this vulnerability by creating a new user namespace and bypassing authorization checks for unattached administrative input/output controls (ioctls). This allows the user to perform unauthorized administrative operations on an inherited network namespace, potentially leading to privilege escalation.

This vulnerability is evaluated as having Moderate impact because it requires local shell access and the ability to create unprivileged user namespaces, limiting the blast radius to unauthorized local network namespace reconfiguration. An unprivileged local attacker can instantiate a child user namespace to gain scoped privileges and issue administrative control requests against an inherited parent network namespace. Although this allows unauthorized manipulation of PPP interfaces across namespaces, it does not directly enable arbitrary kernel memory execution or broader host compromise.

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.