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Fencer Vulns
high 8.2

CVE-2024-26620 json

s390/vfio-ap: always filter entire AP matrix

published 2024-02-29 2 y ago modified 2026-08-05 3 mo ago also EUVD-2024-23882

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

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

s390/vfio-ap: always filter entire AP matrix

The vfio_ap_mdev_filter_matrix function is called whenever a new adapter or domain is assigned to the mdev. The purpose of the function is to update the guest's AP configuration by filtering the matrix of adapters and domains assigned to the mdev. When an adapter or domain is assigned, only the APQNs associated with the APID of the new adapter or APQI of the new domain are inspected. If an APQN does not reference a queue device bound to the vfio_ap device driver, then it's APID will be filtered from the mdev's matrix when updating the guest's AP configuration.

Inspecting only the APID of the new adapter or APQI of the new domain will result in passing AP queues through to a guest that are not bound to the vfio_ap device driver under certain circumstances. Consider the following:

guest's AP configuration (all also assigned to the mdev's matrix): 14.0004 14.0005 14.0006 16.0004 16.0005 16.0006

unassign domain 4 unbind queue 16.0005 assign domain 4

When domain 4 is re-assigned, since only domain 4 will be inspected, the APQNs that will be examined will be: 14.0004 16.0004

Since both of those APQNs reference queue devices that are bound to the vfio_ap device driver, nothing will get filtered from the mdev's matrix when updating the guest's AP configuration. Consequently, queue 16.0005 will get passed through despite not being bound to the driver. This violates the linux device model requirement that a guest shall only be given access to devices bound to the device driver facilitating their pass-through.

To resolve this problem, every adapter and domain assigned to the mdev will be inspected when filtering the mdev's matrix.

Patch / fix

  • Linux Linux 6.1.76, 6.6.15, 6.7.3, 6.8
  • linux Debian 12 6.1.76-1
  • linux Debian 14, Debian 13 6.6.15-1

debian advisories DEBIAN-CVE-2024-26620

  • linux-gcp-6.5 Ubuntu 22.04 LTS 6.5.0-1022.24~22.04.1
  • linux-hwe-6.5 Ubuntu 22.04 LTS 6.5.0-41.41~22.04.2
  • linux-oem-6.5 Ubuntu 22.04 LTS 6.5.0-1024.25
  • linux-azure-6.5 Ubuntu 22.04 LTS 6.5.0-1022.23~22.04.1
  • linux-riscv-6.5 Ubuntu 22.04 LTS 6.5.0-40.40.1~22.04.1
  • linux-nvidia-6.5 Ubuntu 22.04 LTS 6.5.0-1021.22
  • linux-oracle-6.5 Ubuntu 22.04 LTS 6.5.0-1024.24~22.04.1
  • linux-starfive-6.5 Ubuntu 22.04 LTS 6.5.0-1015.16~22.04.1

ubuntu advisories UBUNTU-CVE-2024-26620

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-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1

suse advisories SUSE-SU-2024:1490-1SUSE-SU-2024:1480-1SUSE-SU-2024:1466-1

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-2024-26620 updated cvss 4.4

kernel: s390/vfio-ap: always filter entire AP matrix

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.