CVE-2026-93261

A flaw was found in the Linux kernel's lock dependency validator (lockdep). When lock class registration fails, the kernel omits a check for an empty result before calculating internal index values, leading to memory corruption. A local user can exploit this vulnerability during lock reacquisition to cause an invalid memory dereference, resulting in a kernel crash and Denial of Service (DoS).

A flaw of moderate impact was found in the Linux kernel's lock dependency validator (lockdep). When register_lock_class() fails and returns NULL - for example when the lock class pool is exhausted, the graph lock cannot be acquired, or lock key validation fails - __lock_set_class() uses the NULL return value in pointer arithmetic without first checking it, which corrupts the held lock's internal class index. A subsequent reacquire_held_locks() operation then dereferences that corrupted index, causing a NULL or out-of-bounds memory dereference that crashes the kernel. A local user able to run code on the system can trigger this code path to cause a denial of service; the flaw has no confidentiality or integrity impact. Red Hat Enterprise Linux 6 and 7 are not affected because the vulnerable code is not present in those kernels. The fix is currently deferred for the affected Red Hat Enterprise Linux 8, 9, and 10, Red Hat In-Vehicle OS, and OpenShift Container Platform (RHEL CoreOS) streams; the residual risk of the deferral is limited to local denial of service, since exploitation requires local code execution and a lock class registration failure such as pool exhaustion or key validation failure within the lockdep validator.

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.