Medium [CVE-2026-89751] Linux kernel (x86/tdx): Off-by-one error in port I/O handling
This medium-severity Red Hat Linux advisory covers CVE-2026-89751.
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Summary
A flaw was found in the Linux kernel's x86/tdx component. An off-by-one error in the `handle_in()` and `handle_out()` functions, specifically in the `GENMASK` calculation for port I/O operations, causes the mask to be one bit too wide.
This incorrect handling of I/O sizes could potentially lead to unintended data access or modification during port I/O operations, which may result in information disclosure or data corruption. Red Hat severity: Moderate — CVSS 4.7 (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H).
Weakness: CWE-193.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 30 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 30 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 30 minutes ago·verify at source
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