Skip to content
Fencer Vulns
high 7.8

CVE-2026-23361 json

PCI: dwc: ep: Flush MSI-X write before unmapping its ATU entry

published 2026-03-25 7 mo ago modified 2026-10-30 10 d ago also EUVD-2026-15340

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

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

PCI: dwc: ep: Flush MSI-X write before unmapping its ATU entry

Endpoint drivers use dw_pcie_ep_raise_msix_irq() to raise an MSI-X interrupt to the host using a writel(), which generates a PCI posted write transaction. There's no completion for posted writes, so the writel() may return before the PCI write completes. dw_pcie_ep_raise_msix_irq() also unmaps the outbound ATU entry used for the PCI write, so the write races with the unmap.

If the PCI write loses the race with the ATU unmap, the write may corrupt host memory or cause IOMMU errors, e.g., these when running fio with a larger queue depth against nvmet-pci-epf:

arm-smmu-v3 fc900000.iommu: 0x0000010000000010 arm-smmu-v3 fc900000.iommu: 0x0000020000000000 arm-smmu-v3 fc900000.iommu: 0x000000090000f040 arm-smmu-v3 fc900000.iommu: 0x0000000000000000 arm-smmu-v3 fc900000.iommu: event: F_TRANSLATION client: 0000:01:00.0 sid: 0x100 ssid: 0x0 iova: 0x90000f040 ipa: 0x0 arm-smmu-v3 fc900000.iommu: unpriv data write s1 "Input address caused fault" stag: 0x0

Flush the write by performing a readl() of the same address to ensure that the write has reached the destination before the ATU entry is unmapped.

The same problem was solved for dw_pcie_ep_raise_msi_irq() in commit 8719c64e76bf ("PCI: dwc: ep: Cache MSI outbound iATU mapping"), but there it was solved by dedicating an outbound iATU only for MSI. We can't do the same for MSI-X because each vector can have a different msg_addr and the msg_addr may be changed while the vector is masked.

[bhelgaas: commit log]

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.77, 6.18.17, 6.19.7, 7.0
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.8-1

debian advisories DEBIAN-CVE-2026-23361

  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1046.50
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1061.65

ubuntu advisories UBUNTU-CVE-2026-23361

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-rt Real Time Module 15 SP7 6.4.0-150700.7.37.2
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.37.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.37.2
  • kernel-rt Linux Micro 6.2 6.12.0-160000.28.1
  • kernel-64kb Linux Micro 6.2 6.12.0-160000.28.1
  • kernel-source Linux Micro 6.2 6.12.0-160000.28.1
  • kernel-default Linux Micro 6.2 6.12.0-160000.28.1
  • kernel-default-base Linux Micro 6.2 6.12.0-160000.27.1.160000.2.8

suse advisories SUSE-SU-2026:1573-1SUSE-SU-2026:21237-1SUSE-SU-2026:21230-1SUSE-SU-2026:21255-1SUSE-SU-2026:21123-1SUSE-SU-2026:21114-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.28.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.28.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.28.1

opensuse advisories openSUSE-SU-2026:20572-1

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-2026-23361 updated cvss 5.5

kernel: PCI: dwc: ep: Flush MSI-X write before unmapping its ATU entry

  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • 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 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    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

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.