CVE-2026-93264
Description
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.
Statement
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).
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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