CVE-2026-89751

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

State: Published
Severity: Not scored
Published: Sep 11, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	03149948832a078f759022ed5b92e722d8d23c26 to before c6875423ad849ac234ab9812eb72f37ff8a490b4Affected 03149948832a078f759022ed5b92e722d8d23c26 to before 220011fe95fc78b2bc2d7d43893bc73957a5c811Affected 03149948832a078f759022ed5b92e722d8d23c26 to before 222b7005e4519f633b4cd666226256abbab46a1aAffected 03149948832a078f759022ed5b92e722d8d23c26 to before c4a22154870813d10aa0b4c734a574c726f9d4b0Affected 03149948832a078f759022ed5b92e722d8d23c26 to before bb45f705c4440dd3c689328319b88dd28770bbb8Affected 03149948832a078f759022ed5b92e722d8d23c26 to before 0f63e656b1c679d32ac595de29d10c03efca6a25Affected
LinuxLinux	5.19Affected before 5.19Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.109 through 6.12.Not affected 6.18.50 through 6.18.Not affected 7.2.4 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

03149948832a078f759022ed5b92e722d8d23c26 to before c6875423ad849ac234ab9812eb72f37ff8a490b4Affected
03149948832a078f759022ed5b92e722d8d23c26 to before 220011fe95fc78b2bc2d7d43893bc73957a5c811Affected
03149948832a078f759022ed5b92e722d8d23c26 to before 222b7005e4519f633b4cd666226256abbab46a1aAffected
03149948832a078f759022ed5b92e722d8d23c26 to before c4a22154870813d10aa0b4c734a574c726f9d4b0Affected
03149948832a078f759022ed5b92e722d8d23c26 to before bb45f705c4440dd3c689328319b88dd28770bbb8Affected
03149948832a078f759022ed5b92e722d8d23c26 to before 0f63e656b1c679d32ac595de29d10c03efca6a25Affected

LinuxLinux

5.19Affected
before 5.19Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.109 through 6.12.*Not affected
6.18.50 through 6.18.*Not affected
7.2.4 through 7.2.*Not affected
7.3 and laterNot affected

References

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