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CVE-2026-99168

Linux: mshv_vtl: Check per-CPU register page before mmap

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
Fixed in5c0757b065fbd140d8fbd05dc2c2146b713dfa68Also 874194a8de75fc2f4d1fb70c670b289b7e48f93eCVE List
Published28 Oct 2026Updated 28 Oct 2026CVE List

What fixes it

  • 5c0757b065fbd140d8fbd05dc2c2146b713dfa68LinuxCVE List
  • 874194a8de75fc2f4d1fb70c670b289b7e48f93eLinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

In the Linux kernel, the following vulnerability has been resolved:

mshv_vtl: Check per-CPU register page before mmap

Register-page setup is optional for each CPU. If allocation or registration fails, mshv_vtl_configure_reg_page() warns and leaves that CPU's reg_page NULL, but initial context setup continues successfully. Meanwhile, successful setup on another CPU sets the global mshv_has_reg_page flag.

mshv_vtl_fault() checks this global flag before selecting the requested CPU's register page. With mixed setup results across online CPUs, the check passes even for a CPU with no register page, reaching get_page(NULL) when userspace faults in that mapping.

Check the selected per-CPU register page before taking its reference and return VM_FAULT_SIGBUS if it is absent.

Text from CVE List

Affected versions 6

  • Linuxaffected: 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f before 5c0757b065fbd140d8fbd05dc2c2146b713dfa68CVE List
  • Linuxaffected: 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f before 874194a8de75fc2f4d1fb70c670b289b7e48f93eCVE List
  • Linuxaffected: 6.19CVE List
  • Linuxunaffected: all versions before 6.19CVE List
  • Linuxunaffected: 7.2.13 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 2