CVE tracker / CVE-2026-21248

CVE-2026-21248

CVE-2026-21248 is the Windows Hyper-V Remote Code Execution Vulnerability. Microsoft rates it Important, CVSS 7.3. It is not in CISA's Known Exploited Vulnerabilities catalog. Published February 10, 2026.

Risk summary

HighRemote Code Execution
7.3
CVSS v3 base
1.3%
EPSS: chance of exploitation in 30 days
High
Severity
Important
Microsoft's rating
Less Likely
Microsoft: exploitation
No
In CISA KEV

Microsoft describes it: “Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.”

How to fix it

Microsoft lists 21 affected products and the update that fixes each:

What Microsoft changed

Details

Weakness
CWE-122: Heap-based Buffer Overflow
Publicly disclosed (Microsoft)
No
Exploited (Microsoft)
No
Known exploited (CISA KEV)
Not listed
Published
February 10, 2026
Last revised
February 10, 2026

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References

Microsoft Security Update Guide NVD CVE record CWE

From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.