Affects Microsoft Hyper-V, a widely used enterprise hypervisor; local code execution in host context can disrupt infrastructure and VMs.
CVE-2026-69603
Heap buffer overflow in Microsoft Hyper-V enabling local code execution
Is CVE-2026-69603 being exploited?
Not confirmed. CVE-2026-69603 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 0.31% probability of exploitation in the next 30 days.
How severe is CVE-2026-69603?
CVE-2026-69603 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-2026-69603?
Yes. A fix has been recorded for CVE-2026-69603. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-69603 affect?
CVE-2026-69603 affects Microsoft Hyper-V, Windows Server with Hyper-V role, Windows 10/11 hosts running Hyper-V. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-69603?
Apply Microsoft Hyper-V security updates immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated local attacker can execute arbitrary code in Hyper-V host context, enabling privilege escalation and potential VM/host compromise.
Immediate action required
- affected>= 10.0.14393.0 and < 10.0.14393.9512
- affected>= 10.0.17763.0 and < 10.0.17763.9245
- affected>= 10.0.19044.0 and < 10.0.19044.7725
- affected>= 10.0.19045.0 and < 10.0.19045.7725
- affected>= 10.0.22631.0 and < 10.0.22631.7582
- affected>= 10.0.22631.0 and < 10.0.22631.7582
- affected>= 10.0.26100.0 and < 10.0.26100.9445
- affected>= 10.0.26200.0 and < 10.0.26200.9445
- affected>= 6.2.9200.0 and < 6.2.9200.26349
- affected>= 6.3.9600.0 and < 6.3.9600.23397
- affected>= 6.3.9600.0 and < 6.3.9600.23397
- affected>= 6.2.9200.0 and < 6.2.9200.26349
- affected>= 10.0.14393.0 and < 10.0.14393.9512
- affected>= 10.0.14393.0 and < 10.0.14393.9512
- affected>= 10.0.17763.0 and < 10.0.17763.9245
- affected>= 10.0.17763.0 and < 10.0.17763.9245
- affected>= 10.0.20348.0 and < 10.0.20348.5622
- affected>= 10.0.26100.0 and < 10.0.26100.33438
- affected>= 10.0.26100.0 and < 10.0.26100.33438
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.