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Fencer Vulns
critical 9.8

CVE-2026-46325 in the critical feed json

RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE

published 2026-06-09 5 mo ago modified 2026-10-21 19 d ago also EUVD-2026-35426

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

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

RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE

The current implementation incorrectly handles memory regions (MRs) with page sizes different from the system PAGE_SIZE. The core issue is that rxe_set_page() is called with mr->page_size step increments, but the page_list stores individual struct page pointers, each representing PAGE_SIZE of memory.

ib_sg_to_page() has ensured that when i>=1 either a) SG[i-1].dma_end and SG[i].dma_addr are contiguous or b) SG[i-1].dma_end and SG[i].dma_addr are mr->page_size aligned.

This leads to incorrect iova-to-va conversion in scenarios:

1) page_size < PAGE_SIZE (e.g., MR: 4K, system: 64K): ibmr->iova = 0x181800 sg[0]: dma_addr=0x181800, len=0x800 sg[1]: dma_addr=0x173000, len=0x1000

Access iova = 0x181800 + 0x810 = 0x182010 Expected VA: 0x173010 (second SG, offset 0x10) Before fix: - index = (0x182010 >> 12) - (0x181800 >> 12) = 1 - page_offset = 0x182010 & 0xFFF = 0x10 - xarray[1] stores system page base 0x170000 - Resulting VA: 0x170000 + 0x10 = 0x170010 (wrong)

2) page_size > PAGE_SIZE (e.g., MR: 64K, system: 4K): ibmr->iova = 0x18f800 sg[0]: dma_addr=0x18f800, len=0x800 sg[1]: dma_addr=0x170000, len=0x1000

Access iova = 0x18f800 + 0x810 = 0x190010 Expected VA: 0x170010 (second SG, offset 0x10) Before fix: - index = (0x190010 >> 16) - (0x18f800 >> 16) = 1 - page_offset = 0x190010 & 0xFFFF = 0x10 - xarray[1] stores system page for dma_addr 0x170000 - Resulting VA: system page of 0x170000 + 0x10 = 0x170010 (wrong)

Yi Zhang reported a kernel panic[1] years ago related to this defect.

Solution: 1. Replace xarray with pre-allocated rxe_mr_page array for sequential indexing (all MR page indices are contiguous) 2. Each rxe_mr_page stores both struct page* and offset within the system page 3. Handle MR page_size != PAGE_SIZE relationships: - page_size > PAGE_SIZE: Split MR pages into multiple system pages - page_size <= PAGE_SIZE: Store offset within system page 4. Add boundary checks and compatibility validation

This ensures correct iova-to-va conversion regardless of MR page size and system PAGE_SIZE relationship, while improving performance through array-based sequential access.

Tests on 4K and 64K PAGE_SIZE hosts: - rdma-core/pytests $ ./build/bin/run_tests.py --dev eth0_rxe - blktest: $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd

[1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/

Patch / fix

  • Linux Linux 6.3, 6.6.160, 6.12.114, 6.18.14, 6.19.4, 7.0
  • linux Debian 13 6.12.115-2
  • linux Debian 14 6.18.14-1

debian advisories DEBIAN-CVE-2026-46325

  • linux Ubuntu 24.04 LTS 6.8.0-137.137
  • linux Ubuntu 25.10 6.17.0-40.40
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1062.65
  • linux-aws Ubuntu 25.10 6.17.0-1019.19
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1065.73
  • linux-gcp Ubuntu 25.10 6.17.0-1020.22
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1060.68
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1062.63

ubuntu advisories UBUNTU-CVE-2026-46325

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.53.1.el9_8
  • rv RHEL 9 5.14.0-687.53.1.el9_8
  • perf RHEL 9 5.14.0-687.53.1.el9_8
  • rtla RHEL 9 5.14.0-687.53.1.el9_8
  • libperf RHEL 9 5.14.0-687.53.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.53.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.53.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.53.1.el9_8

red hat advisories RHSA-2026:72623

  • kernel AlmaLinux 9 5.14.0-687.53.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.53.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.53.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.53.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.53.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.53.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.53.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.53.1.el9_8

almalinux advisories ALSA-2026:72623

  • kernel Rocky Linux 9 5.14.0-687.53.1.el9_8

rocky linux advisories RLSA-2026:72623

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-46325 updated cvss 7.0

kernel: RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE

  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.53.1.el9_8, perf 5.14.0-687.53.1.el9_8, rtla 5.14.0-687.53.1.el9_8, python3-perf 5.14.0-687.53.1.el9_8, kernel-devel-matched 5.14.0-687.53.1.el9_8, kernel-64k-devel-matched 5.14.0-687.53.1.el9_8, +7 more Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.53.1.el9_8, kernel-64k 5.14.0-687.53.1.el9_8, kernel-core 5.14.0-687.53.1.el9_8, kernel-tools 5.14.0-687.53.1.el9_8, kernel-modules 5.14.0-687.53.1.el9_8, kernel-64k-core 5.14.0-687.53.1.el9_8, +27 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.53.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.53.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.53.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.53.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.53.1.el9_8 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.53.1.el9_8, kernel-rt-64k 5.14.0-687.53.1.el9_8, kernel-rt-core 5.14.0-687.53.1.el9_8, kernel-rt-modules 5.14.0-687.53.1.el9_8, kernel-rt-64k-core 5.14.0-687.53.1.el9_8, kernel-rt-debug-core 5.14.0-687.53.1.el9_8, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.53.1.el9_8, kernel-rt-core 5.14.0-687.53.1.el9_8, kernel-rt-modules 5.14.0-687.53.1.el9_8, kernel-rt-debug-core 5.14.0-687.53.1.el9_8, kernel-rt-modules-core 5.14.0-687.53.1.el9_8, kernel-rt-debug-modules 5.14.0-687.53.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:72623
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
24 d ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound
Technology feeds

References

Sources

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