---
id: CVE-2026-74515
title: |-
  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.…
summary: |-
  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.…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-772
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - enterprise_linux_baseos_v_8
  - enterprise_linux_crb_v_8
  - enterprise_linux_nfv_v_8
  - enterprise_linux_rt_v_8
patched:
  - enterprise_linux_baseos_v_8
  - enterprise_linux_crb_v_8
  - enterprise_linux_nfv_v_8
  - enterprise_linux_rt_v_8
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:34.017'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74515'
references:
  - url: 'https://git.kernel.org/stable/c/591952b63a9f976da7d49f719f36ec826ee2a575'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/642d2d1067f7c4d753ae0e3ba5bc98b43cfe3c70'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6837f0ae85fd54cf64c8a0c7c530bba2fae0a207'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6be1ff49ba81f96a6fa55915e6d920be43ac57cc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/78d9648e7e960546d5b72504a0b0358cd8bb1e9d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8fa01be5a6149404adb82c0979a78f6347edd3ef'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74515.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-74515'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2517006'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-74515'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74515'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081543-CVE-2026-74515-dcb8@gregkh/T
  - url: 'https://access.redhat.com/errata/RHSA-2026:89816'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89814'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00129
epssPercentile: 0.02535
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:58:46.342564Z'
scores:
  nvd: 8.8
  vendor: 6.1
  cna: 8.8
ingestedAt: '2026-10-16T19:46:24.350Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:89816** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89816)
- **RHSA-2026:89814** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89814)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74515.json)