Buffer Overflow Vulnerability in Linux Kernel Hypervisor Driver

CVE-2026-31786

What is CVE-2026-31786?

A buffer overflow vulnerability was identified in the Linux kernel within the hypervisor driver located in drivers/xen/sys-hypervisor.c. This issue arises due to the improper handling of the build ID returned by the HYPERVISOR_xen_version function, which is neither NUL terminated nor a valid string. The affected function, buildid_show, utilizes sprintf, which attempts to read and copy data until a NUL terminator is found, potentially leading to overflow. The solution replaces sprintf with memcpy to correctly handle the buffer, ensuring that no overflow occurs during data operations.

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