CVE-2026-21248 EXPLOIT
7.3
HIGH · CVSS 3.1 · EPSS 1.3% (pctl 70)
Patch early
A public exploit exists.
Description
Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
Scoring
| CVSS | 7.3 (HIGH, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
| EPSS | 1.33% — more likely to be exploited than 70% of all CVEs |
| Weakness | CWE-122 |
| On CISA KEV | no |
| Public exploit | yes |
| Published | 2026-02-10 |
| Last modified | 2026-06-17 |
Affected (12)
| Vendor | Product |
|---|---|
| microsoft | windows 10 1607 |
| microsoft | windows 10 1809 |
| microsoft | windows 10 21h2 |
| microsoft | windows 10 22h2 |
| microsoft | windows 11 23h2 |
| microsoft | windows 11 24h2 |
| microsoft | windows 11 25h2 |
| microsoft | windows server 2016 |
| microsoft | windows server 2019 |
| microsoft | windows server 2022 |
| microsoft | windows server 2022 23h2 |
| microsoft | windows server 2025 |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Windows 11 25H2 - Heap Overflow | 2026-04-30 |
→ the Explorer · watch your stack · NVD