CVE-2026-53133

Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source

AV:LAttack vector, local

Vulnerable code is reached through local RDMA uverbs operations such as opening `/dev/infiniband/uverbsX` and issuing memory-registration commands. Remote RDMA traffic may later exercise a bad MR, but the vulnerable iterator is invoked by local userspace registration, not by network packet parsing.

AC:LAttack complexity, low

There is no race or probabilistic condition; on an affected RDMA/IOMMU deployment the attacker controls the MR address, length, and access flags needed to request large aligned mappings. Hardware/IOMMU support is an environmental prerequisite for the affected subsystem, not an exploitation step beyond attacker control.

PR:LPrivileges required, low

The uverbs device node is created world-accessible and MR registration does not require CAP_SYS_ADMIN or CAP_NET_ADMIN, though the process must be an unprivileged local user able to use the RDMA device and pin memory under its memlock limits. No real init-namespace root privilege is required.

UI:NUser interaction, none

After local access to the RDMA device, the attacker can perform the open/context/PD/MR registration sequence directly. No separate victim action is required.

S:UScope, unchanged

The impact remains within the kernel/RDMA device memory-management security authority. This is not a guest-to-host escape, IOMMU boundary bypass by a guest, or another cross-scope boundary change.

C:HConfidentiality impact, high

The truncation can program wrong DMA addresses into RDMA memory translation tables for blocks after the overflow. With RDMA read-capable access, the resulting mistranslation can expose unintended memory reachable through the device mapping, so the higher defensible confidentiality impact is High.

I:HIntegrity impact, high

The same wrong DMA translation can be used with local or remote write-capable MR permissions to direct RDMA writes to unintended mapped memory. Because this is device DMA memory corruption rather than a bounded metadata error, the higher defensible integrity impact is High.

A:HAvailability impact, high

Incorrect DMA translations can cause IOMMU/device faults, corrupted RDMA state, or repeated failures of registered memory operations. Given the kernel/device-level DMA fault surface and the requirement to choose the higher severity when uncertain, availability impact is High.