CVE-2026-74515
KVM (s390) ioctl flaw can let a guest corrupt host resources and enable host compromise.
Is CVE-2026-74515 being exploited?
Not confirmed. CVE-2026-74515 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.13% probability of exploitation in the next 30 days.
How severe is CVE-2026-74515?
CVE-2026-74515 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-74515?
Yes. A fix has been recorded for CVE-2026-74515. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-74515 affect?
CVE-2026-74515 affects Linux kernel (KVM on s390/zSeries), zPCI devices, IBM Z / zSeries virtualized hosts. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-74515?
Upgrade s390 Linux kernel to the fixed release and isolate/untrust guests until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
A guest can trigger repeated adapter-interrupt registration, overwriting resources and enabling host privilege escalation / RCE against the hypervisor.
Immediate action required
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 642d2d1067f7c4d753ae0e3ba5bc98b43cfe3c70
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 78d9648e7e960546d5b72504a0b0358cd8bb1e9d
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 6be1ff49ba81f96a6fa55915e6d920be43ac57cc
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 6837f0ae85fd54cf64c8a0c7c530bba2fae0a207
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 591952b63a9f976da7d49f719f36ec826ee2a575
- affected>= 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and < 8fa01be5a6149404adb82c0979a78f6347edd3ef
- affected6.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.