CVE-2026-80679

A flaw was found in the Linux kernel. Specifically, within the s390/dasd component, the dasd_release_space() function incorrectly checks a function pointer by using a logical AND operator instead of a logical OR operator. This error can lead to a NULL pointer dereference, which may cause a system crash and result in a denial of service.

A low severity flaw was found in the Linux kernel s390/dasd driver on IBM Z (s390) systems. The dasd_release_space() function checks the is_ese() discipline function pointer using a logical AND operator instead of a logical OR operator, so the callback can be invoked even when it is NULL. A local user with access to the DASD block device ioctl path can trigger this condition when release-space handling reaches a device discipline that does not implement is_ese(), causing a NULL pointer dereference that crashes the kernel and results in a denial of service. There is no impact to confidentiality or integrity. Red Hat Enterprise Linux 6, 7, and 8 (kernel and kernel-rt) are not affected because the vulnerable code is not present in those releases. Red Hat Enterprise Linux 9 and 10 (kernel and kernel-rt) and Red Hat In-Vehicle OS 2 are affected; the fix is currently deferred because this is a low-impact, architecture-specific denial of service that requires local access to the s390 DASD device control path, and the residual risk is limited to a local kernel crash on affected systems. Although the CVSS:3.1 base score for this flaw is 5.5 (MODERATE), Red Hat rates the overall impact as LOW because exploitation requires local access to s390 DASD hardware and the only consequence is loss of availability.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.