Bug 2532152 (CVE-2026-89751) - CVE-2026-89751 kernel: x86/tdx: Fix off-by-one in port I/O handling
Summary: CVE-2026-89751 kernel: x86/tdx: Fix off-by-one in port I/O handling
Keywords:
Status: NEW
Alias: CVE-2026-89751
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 20:58 UTC by OSIDB Bzimport
Modified: 2026-09-21 17:00 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-09-11 20:58:39 UTC
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.


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