CVE-2026-89751

Summary

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

x86/tdx: Fix off-by-one in port I/O handling

handle_in() and handle_out() in arch/x86/coco/tdx/tdx.c use:

u64 mask = GENMASK(BITS_PER_BYTE * size, 0);

GENMASK(h, l) includes bit h. For size=1 (INB), this produces GENMASK(8, 0) = 0x1FF (9 bits) instead of GENMASK(7, 0) = 0xFF (8 bits). The mask is one bit too wide for all I/O sizes.

Fix the mask calculation.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux03149948832a078f759022ed5b92e722d8d23c26 < 222b7005e4519f633b4cd666226256abbab46a1aaffected
LinuxLinux03149948832a078f759022ed5b92e722d8d23c26 < c4a22154870813d10aa0b4c734a574c726f9d4b0affected
LinuxLinux03149948832a078f759022ed5b92e722d8d23c26 < bb45f705c4440dd3c689328319b88dd28770bbb8affected
LinuxLinux03149948832a078f759022ed5b92e722d8d23c26 < 0f63e656b1c679d32ac595de29d10c03efca6a25affected
LinuxLinux5.19affected
LinuxLinux0 < 5.19unaffected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References