SB2026082786 - Improper input validation in Linux kernel s390 cio driver

Description

This security bulletin contains information about 1 vulnerability.

1) Improper input validation (CVE-ID: CVE-2026-80551)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to execute arbitrary code or cause a denial of service.

The vulnerability exists due to improper input validation in the vfio_ccw channel program IDAW handling when reading the first IDAW and then processing the full IDAL. A remote attacker can trigger inconsistent IDAW reads to execute arbitrary code or cause a denial of service.

The issue affects the s390 vfio_ccw subsystem and arises because the first IDAW is read separately from the full IDAL.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/08ef2a82115690d6e229615872ac1731af732497
• https://git.kernel.org/stable/c/0d46c2565f173bcddcdcaf44a4f69789a20535e2
• https://git.kernel.org/stable/c/565bef268d75bf7df665bce6923a88cd0eb74592
• https://git.kernel.org/stable/c/fc59e9482117ebdccd6dc7fa8082f8b980fd021e