SB2026091221 - Off-by-one in Linux kernel coco tdx
Published: September 12, 2026
Security Bulletin ID
SB2026091221
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Off-by-one (CVE-ID: CVE-2026-89751)
CWE-ID: CWE-193 - Off-by-one Error
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause incorrect port I/O handling.
The vulnerability exists due to an off-by-one error in handle_in() and handle_out() in arch/x86/coco/tdx/tdx.c when emulating port I/O operations. A local user can perform port I/O operations that invoke the affected handlers to cause incorrect port I/O handling.
Remediation
Install update from vendor's website.