CVE-2026-98361

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rxe: Restore HMM_PFN_WRITE check in ODP write paths

Commit 0b261d7c1cd3 ("RDMA/rxe: Break endless pagefault loop for RO

pages") dropped the access permission test from rxe_check_pagefault()

and left only HMM_PFN_VALID. A page faulted in read-only, for example

a page-cache folio behind a PROT_READ file mapping, then satisfies the

check and ODP write operations (RDMA WRITE, RDMA READ response, SEND

payload, atomics) modify it through kmap without ever breaking CoW.

An unprivileged user can register an ODP MR over such a mapping and

have incoming RDMA traffic overwrite the page cache of a file it only

holds O_RDONLY, including /etc/passwd or setuid binaries. This is the

same primitive class as Dirty COW and CVE-2022-2590.

mlx5 has the missing invariant: its ODP path sets the device write bit

only for pfns that carry HMM_PFN_WRITE. Restore it in rxe by requiring

HMM_PFN_WRITE in rxe_check_pagefault() for every ope

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References