RDMA Vulnerability in Linux Kernel Affects Multiple Drivers

CVE-2026-52908

What is CVE-2026-52908?

The vulnerability in the Linux kernel's RDMA subsystem pertains to improper handling of memory region (MR) re-registration, specifically concerning the REREG_ACCESS flag. When the access flag transitions from read-only (RO) to read-write (RW), the underlying memory management structures must be rigorously validated to ensure they comply with the RW permissions. The introduction of a new function, ib_umem_check_rereg(), requires that drivers verify their configurations before processing changes. In particular, the mlx4 driver has to maintain a strict check due to its sequential handling of REREG_ACCESS and REREG_TRANS combinations, limiting its support for such transitions.

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