CVE-2025-38257

A flaw was found in the Linux kernel's s390/pkey component. A local user could exploit an integer overflow vulnerability in the memdup_user() size calculation when handling apqn target list entries. This overflow can cause the allocated memory size to be out of sync with the described size, leading to unpredictable system behavior and potentially a denial of service (DoS).

A moderate severity flaw was found in the Linux kernel's s390/pkey (protected key) support on the s390x architecture. A local user could supply a number of APQN target list entries through an ioctl such that the size calculation used for memdup_user() overflows, leaving the allocated memory smaller than the size value describing it. This mismatch can lead to unpredictable kernel behavior, potentially resulting in a denial of service. Red Hat rated this flaw moderate (CVSS 6.7) because exploitation requires a local user with high privileges, whereas NIST scored it 7.8 (important) assuming low privileges. The vulnerable code is present in the Red Hat Enterprise Linux 9 kernel and kernel-rt packages and the Red Hat Enterprise Linux 10 kernel package, and the fix for these releases is currently deferred, leaving a residual risk that a sufficiently privileged local user on an affected s390x system could trigger this behavior. Red Hat Enterprise Linux 6, 7, and 8, and Red Hat In-Vehicle OS are not affected because the vulnerable code is not present in those products.

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.