CVE-2026-74334

A flaw was found in the RDMA/nldev component of the Linux kernel. Improper locking during memory region re-registration (rereg_mr) can lead to a race condition when accessing protection domains (PD). This vulnerability could result in unpredictable system behavior or a denial of service due to concurrent, unsynchronized memory access.

A race condition flaw rated Moderate severity was found in the RDMA/nldev component of the Linux kernel as shipped in Red Hat Enterprise Linux and Red Hat In-Vehicle OS. When a memory region is re-registered and moved to a different protection domain (rereg_mr), the nldev netlink resource-dump paths accessed the mr->pd pointer without proper locking, so a concurrent dump could read a stale protection-domain pointer, resulting in unpredictable system behavior or a denial of service (kernel crash). Exploitation requires a local user with access to the RDMA userspace verbs and netlink resource-dump interfaces, and successful triggering depends on precise timing of the race. Red Hat Enterprise Linux 7, 8, 9, and 10 (kernel and kernel-rt) and Red Hat In-Vehicle OS 2 are affected. The fix is deferred to a future maintenance update rather than an immediate erratum because Red Hat rates this issue as Moderate and exploitation requires local access and a timing-dependent race; the residual risk is therefore limited to local denial of service. Red Hat's Moderate rating (CVSS 5.5, availability impact only) differs from the upstream CVEORG Important rating (7.8) because Red Hat's analysis found no evidence of reliable confidentiality or integrity impact from this race.

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. The upstream advisory recommends updating to the latest stable kernel version, which contains the fix for this issue.