# CVE-2024-26620: linux: In the Linux kernel, the following vulnerability has been resolved:  s390/vfio-ap: always filter entire AP matrix  Th...

CVE-2024-26620 is fixed in linux on 1 platform, first by DEBIAN-CVE-2024-26620, released March 11, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2024-26620
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0063
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 11, 2024

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.76-1 | [DEBIAN-CVE-2024-26620](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26620.md) | Mar 11, 2024 |
| Linux | linux Debian 13.5 (trixie) | 6.6.15-1 | [DEBIAN-CVE-2024-26620](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26620.md) | Mar 11, 2024 |
| Linux | linux Debian 14 | 6.6.15-1 | [DEBIAN-CVE-2024-26620](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26620.md) | Mar 11, 2024 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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