CVE-2026-64229

Name of the Vulnerable Software and Affected Versions Linux kernel version 7.1.0-rc3

Description An issue exists in the x86 memory management where broadcast TLB flushing remains enabled on AMD CPUs that support INVLPGB even when the system is booted with the nopcid option. This occurs because the functions mm global asid() and consider global asid() rely on the X86 FEATURE INVLPGB feature. When a memory descriptor becomes active on more than three CPUs, consider global asid() assigns it a global ASID, leading flush tlb mm range() to execute the broadcast tlb flush() path using a non-zero PCID. If CR4.PCIDE is not set, issuing an INVLPGB with a non-zero PCID triggers a general protection fault (#GP). TLB (Translation Lookaside Buffer) is a hardware cache used by the memory management unit to improve virtual-to-physical address translation speed.

Recommendations Update Linux kernel version 7.1.0-rc3 to a version where X86 FEATURE INVLPGB is made dependent on X86 FEATURE PCID to ensure broadcast TLB support is disabled when PCID is disabled.