Linux Kernel CVE-2026-68473

The primary fix is upgrading to Linux kernel 7.1.5 or applying the stable patch commits directly: https://git.kernel.org/stable/c/d610d3ab18197d87618da11ec5fe8b3cebf32208 for the 7.1.x branch and https://git.kernel.org/stable/c/d5c234774a82f27b594f70c15fc45ce3648e4295 for the 7.2 branch. Both commits correct the single-symbol error from CONFIG_E500 to CONFIG_PPC_E500 in mask_user_address(), restoring the ISEL-based address masking. No runtime workaround exists - the broken code path is a compile-time omission that cannot be patched without rebuilding the kernel. As a compensating control for E500 systems that cannot be immediately patched, administrators should restrict local shell and code execution access to fully trusted accounts only, since PR:L (local low-privilege) is the required attack precondition. Note that tightening local access removes the exploitation prerequisite entirely but may affect legitimate multi-user workflows. Upstream fix availability is confirmed via git.kernel.org stable commits; a released patched version (7.1.5) is listed in EUVD data but should be independently verified against the distribution's release notes before deployment.