{"id":"CVE-2026-98361","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Restore HMM_PFN_WRITE check in ODP write paths\n\nCommit 0b261d7c1cd3 (\"RDMA/rxe: Break endless pagefault loop for RO\npages\") dropped the access permission test…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Restore HMM_PFN_WRITE check in ODP write paths\n\nCommit 0b261d7c1cd3 (\"RDMA/rxe: Break endless pagefault loop for RO\npages\") dropped the access permission test…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 0b261d7c1cd32dc93cbc92425fb55e67b24c6638 < c6f56982ec5c7da83c4bdfcce3b6db18bcfe6425","Linux >= 0b261d7c1cd32dc93cbc92425fb55e67b24c6638 < 2d6c6f94d3e1cde049fe5db71dbd5549f10b2de1","Linux >= 0b261d7c1cd32dc93cbc92425fb55e67b24c6638 < 769001ce838d907ecaa95f1d0a4e8fc86f761f9f","Linux 6.16"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:29.960","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98361","references":[{"url":"https://git.kernel.org/stable/c/2d6c6f94d3e1cde049fe5db71dbd5549f10b2de1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/769001ce838d907ecaa95f1d0a4e8fc86f761f9f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c6f56982ec5c7da83c4bdfcce3b6db18bcfe6425","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.393Z","slug":"CVE-2026-98361","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Restore HMM_PFN_WRITE check in ODP write paths\n\nCommit 0b261d7c1cd3 (\"RDMA/rxe: Break endless pagefault loop for RO\npages\") dropped the access permission test from rxe_check_pagefault()\nand left only HMM_PFN_VALID. A page faulted in read-only, for example\na page-cache folio behind a PROT_READ file mapping, then satisfies the\ncheck and ODP write operations (RDMA WRITE, RDMA READ response, SEND\npayload, atomics) modify it through kmap without ever breaking CoW.\n\nAn unprivileged user can register an ODP MR over such a mapping and\nhave incoming RDMA traffic overwrite the page cache of a file it only\nholds O_RDONLY, including /etc/passwd or setuid binaries. This is the\nsame primitive class as Dirty COW and CVE-2022-2590.\n\nmlx5 has the missing invariant: its ODP path sets the device write bit\nonly for pfns that carry HMM_PFN_WRITE. Restore it in rxe by requiring\nHMM_PFN_WRITE in rxe_check_pagefault() for every operation except\nRXE_PAGEFAULT_RDONLY. A write to a non-writable VMA now fails the one\nfault attempt with -EPERM from hmm_vma_fault() instead of re-faulting\nforever. For a writable VMA the fault breaks CoW and the write lands\nin the private page.\n\nKeep pmem flushes on the read-only check. arch_wb_cache_pmem() never\nmodifies memory, and the FLUSH access bits do not make the umem\nwritable, so classifying flushes as writes would make every flush\nagainst a flush-only MR fail.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}