CVE-2026-93264

A flaw was found in the Linux kernel's Elastic Fabric Adapter (EFA) driver within the Remote Direct Memory Access (RDMA) subsystem. This vulnerability allows a local user to cause a denial of service (DoS) or memory corruption by registering a memory region with a specific page count. Due to an incorrect buffer chunk length calculation in indirect page buffer lists, the driver improperly indexes the chunk array, leading to an out-of-bounds memory access.

A moderate severity flaw was found in the Linux kernel's RDMA Elastic Fabric Adapter (EFA) driver. When registering a memory region that uses an indirect page buffer list (PBL), a page count that is an exact multiple of EFA_PTRS_PER_CHUNK (510) causes the length of the last, fully populated chunk to be wrongly computed as zero, and the driver indexes the chunk array out of bounds. A local user with access to the EFA RDMA device can trigger this flaw by registering a memory region with a specific page count, resulting in memory corruption or a denial of service (the device may reject the memory registration, or the kernel may crash). Red Hat rated this flaw Moderate impact with CVSS 3.1 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), reflecting the availability impact of the out-of-bounds access.

The kernel packages in Red Hat Enterprise Linux 8, 9, and 10 (including the kernel-rt variant), Red Hat In-Vehicle OS 2, and OpenShift Container Platform 4 releases that ship the RHEL CoreOS 9 kernel are affected. Red Hat Enterprise Linux 6 and 7 Extended Lifecycle Support are not affected because the vulnerable code is not present in those kernel versions.

The fix for the affected Red Hat product versions is currently deferred to a future scheduled kernel update. Because exploitation requires local access to a system with EFA RDMA hardware, exposure is limited; until a fixed kernel is released, the residual risk is that such a local user could corrupt kernel memory or crash the system (denial of service).

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.