CVE-2026-89751

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

N/A
Published: September 11, 2026 at 07:46 PM UTC
Updated: October 19, 2026 at 09:18 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
N/A
Exploit prediction
EPSS 0.2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

03149948832a078f759022ed5b92e722d8d23c263149948832a78f759022ed5b92e722d8d23c265.19
Vendor states this is fixed in 0f63e656b1c679d32ac595de29d10c03efca6a25 (fixed)
Vendor states this is fixed in 220011fe95fc78b2bc2d7d43893bc73957a5c811 (fixed)
Vendor states this is fixed in 222b7005e4519f633b4cd666226256abbab46a1a (fixed)
Vendor states this is fixed in bb45f705c4440dd3c689328319b88dd28770bbb8 (fixed)
Vendor states this is fixed in c4a22154870813d10aa0b4c734a574c726f9d4b0 (fixed)
Vendor states this is fixed in c6875423ad849ac234ab9812eb72f37ff8a490b4 (fixed)
Vendor states this is fixed in 5.19 (unaffected)
Vendor states this is fixed in 6.1.188 (unaffected)
Vendor states this is fixed in 6.12.109 (unaffected)
Vendor states this is fixed in 6.18.50 (unaffected)
Vendor states this is fixed in 6.6.157 (unaffected)
Vendor states this is fixed in 7.2.4 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

Quick Info

StatusRECEIVED

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