CVE-2026-74515

Received Received - Intake

KVM: s390 zPCI Adapter Interrupt Forwarding Rejection

Publication date: 2026-08-15

Last updated on: 2026-08-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: pci: Reject adapter interrupt forwarding if already enabled The MPCIFC instruction doesn't allow registering adapter interrupts without first unregistering. So reject any request to enable interrupt forwarding if its already enabled for the zPCI device. This also fixes overwriting and thus leaking resources when the ioctl is called multiple times for the same device.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-19

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74515

EUVD

EUVD-2026-59708

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a flaw in the KVM (Kernel-based Virtual Machine) for s390 (IBM Z) systems. The issue occurs when the MPCIFC instruction attempts to register adapter interrupts without first unregistering existing ones. This can lead to resource overwriting and leaks if the ioctl is called multiple times for the same device.

Detection Guidance

This vulnerability is specific to the Linux kernel's KVM s390 pci module and does not have network-based detection methods. Detection requires checking kernel logs or running commands on the affected system to identify improper adapter interrupt forwarding attempts.

Impact Analysis

This vulnerability could allow an attacker with access to a virtual machine to cause resource leaks or corruption in the host system. This might lead to denial-of-service conditions or instability in the affected system.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a low-level kernel issue in KVM for s390 systems that could lead to resource leaks but does not involve data exposure or privacy violations.

Mitigation Strategies

Update the Linux kernel to the latest patched version to address the KVM s390 pci adapter interrupt forwarding issue. Monitor zPCI device configurations for unexpected interrupt forwarding states.

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