CVE-2026-53133

A flaw was found in the Linux kernel's RDMA/umem component. When the IOMMU (Input/Output Memory Management Unit) is used, a very large memory block can be split across multiple scatter-gather (SG) entries. During the reassembly of these split SG entries, an issue with truncation for block sizes greater than or equal to 4 gigabytes (4G) can lead to an overflow of 32-bit stack values. This results in the computation of incorrect DMA (Direct Memory Access) addresses, potentially causing data corruption or system instability.

This vulnerability is rated as having Moderate impact because triggering the condition requires local unprivileged access to RDMA subsystems, active IOMMU support, and an unusually large memory registration of four gigabytes or greater. InfiniBand and RDMA technologies are primarily utilized in specialized clustering or high-performance computing environments, meaning standard enterprise installations without RDMA devices remain unexposed. Although improper address calculation during buffer handling can result in memory corruption or host instability, the specialized hardware prerequisites and local access requirement limit overall risk.

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.