CVE-2026-68454: KVM: s390: pci: Fix handling of AIF enable without AISB

CSIRTS triage

What

The KVM s390 PCI handler incorrectly handles AIF (Adapter Interrupt Forwarding) enable requests without AISB (Adapter Interrupt Summary Bit).

Who is affected

IBM System z (s390) systems running Linux KVM with PCI device passthrough.

Urgency

Medium priority; improper interrupt handling can affect VM isolation.

Action

Apply Linux kernel patch to validate AISB presence before handling AIF enable.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source

Microsoft Security Response Center (INTL · vendor-psirt · site)

Severity

medium — CVSS 5.5

Published

2026-08-11

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68454

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

• Low exploitation riskCVE-2026-684540.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

• medium[NEW] [medium] Linux Kernel: Multiple vulnerabilitiescert-bund
• highCVE-2026-68454: In the Linux kernel, the following vulnerability has been resolved: KVM: s390: pci: Fix handli…nvd

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