CVE-2026-31788

A flaw was found in the Linux kernel's Xen privcmd driver. This vulnerability allows a root user process within an unprivileged guest (domU) to issue arbitrary hypercalls. Such an action could enable the process to modify the kernel's memory, thereby undermining the secure boot feature designed to protect system integrity.

A security issue in the Xen privcmd driver allows a root process inside a guest domain to issue unrestricted hypercalls, which can modify kernel memory and bypass secure boot guarantees. This breaks the intended isolation and trust model by allowing a privileged guest user to affect kernel integrity. For the CVSS the PR:H is used for the base score because exploitation requires root access inside the guest domain. The issue is local to Xen environments.

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.