CVE Catalog

CVE-2026-89751

Low risk· EPSS 6%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

6th percentile - higher than 6% of all known CVEs

Summary

On x86, TDX port I/O handling (handle_in() and handle_out()) uses the mask GENMASK(BITS_PER_BYTE * size, 0), which includes the high bit. For size=1 this yields a 9-bit mask 0x1FF instead of the 8-bit 0xFF, making the mask one bit too wide for all I/O sizes.

Risk Assessment

The incorrect mask can lead to improper handling of I/O operations in TDX environments, potentially causing unexpected behavior or errors in device communication. This may affect the integrity of data transferred through I/O ports.

Recommendation

Update the Linux kernel to a version containing the mask calculation fix in arch/x86/coco/tdx/tdx.c. After updating, verify correct I/O operation behavior in the TDX environment.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS