Memory Management Vulnerability in Linux Kernel Affects RDMA/irdma

CVE-2026-43120

What is CVE-2026-43120?

A vulnerability exists in the Linux kernel's RDMA/irdma subsystem, specifically concerning memory registration and deregistration processes. When the IB_MR_REREG_TRANS flag is enabled during the rereg_user_mr operation, an improper handling of memory regions can occur, leading to a double free scenario. If the re-registration process encounters any failures after allocating a new user memory (umem), it inadvertently retains a pointer to the previous umem. This results in potential instability when the user attempts to deregister the memory region, as the system may try to release an already freed resource. The issue has been addressed by ensuring that the memory region pointer is set to NULL after the user memory release, preventing erroneous attempts to free it again.

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