An off‑by‑one error in the kernel’s TDX port I/O handlers causes the mask used for 8‑bit access to be one bit too wide, producing a 9‑bit mask instead of the intended 8 bits. This leads to incorrect data being read from or written to I/O ports, potentially corrupting kernel data. Based on the description, it is inferred that exploitation requires local kernel privilege or a user with TDX port I/O access.

The issue is confined to the Linux kernel on x86 architectures where arch/x86/coco/tdx/tdx.c is compiled. Any kernel build that has not incorporated the patch is vulnerable; the CPE entry identifies the general Linux kernel product but does not specify affected version ranges.

Based on the description, it is inferred that exploitation requires local kernel privilege or a user with TDX port I/O access. The CVSS score of 4.7 indicates moderate severity, while the EPSS score of less than 1% reflects a very low likelihood of exploitation. The vulnerability is not listed in CISA KEV. Exploitation requires local kernel access or a privileged actor capable of performing TDX port I/O, with no known remote code execution path. Thus the risk is considered low to moderate, depending on the environment.