CVE-2026-21248
published 2026-02-10CVE-2026-21248: Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
PriorityP354high7.3CVSS 3.1
AVLACLPRLUIRSUCHIHAH
EXPLOIT
EPSS
1.24%
66.1th percentile
Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
Affected
38 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | windows_10_1607 | < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_10_1809 | < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_10_21h2 | < 10.0.19044.6937 | 10.0.19044.6937 |
| microsoft | windows_10_22h2 | < 10.0.19045.6937 | 10.0.19045.6937 |
| microsoft | windows_10_version_1607 | >= 10.0.14393.0 < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_10_version_1809 | >= 10.0.17763.0 < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_10_version_21h2 | >= 10.0.19044.0 < 10.0.19044.6937 | 10.0.19044.6937 |
| microsoft | windows_10_version_22h2 | >= 10.0.19045.0 < 10.0.19045.6937 | 10.0.19045.6937 |
| microsoft | windows_11_23h2 | < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_24h2 | < 10.0.26100.7781 | 10.0.26100.7781 |
| microsoft | windows_11_25h2 | < 10.0.26200.7781 | 10.0.26200.7781 |
| microsoft | windows_11_version_22h3 | >= 10.0.22631.0 < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_version_24h2 | >= 10.0.26100.0 < 10.0.26100.7840 | 10.0.26100.7840 |
| microsoft | windows_11_version_25h2 | >= 10.0.26200.0 < 10.0.26200.7840 | 10.0.26200.7840 |
| microsoft | windows_11_version_26h1 | >= 10.0.28000.0 < 10.0.28000.1575 | 10.0.28000.1575 |
| microsoft | windows_server_2016 | < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_server_2016 | >= 10.0.14393.0 < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_server_2019 | < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_server_2019 | >= 10.0.17763.0 < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_server_2022 | < 10.0.20348.4711 | 10.0.20348.4711 |
| microsoft | windows_server_2022 | >= 10.0.20348.0 < 10.0.20348.4773 | 10.0.20348.4773 |
| microsoft | windows_server_2022_23h2 | < 10.0.25398.2149 | 10.0.25398.2149 |
| microsoft | windows_server_2025 | < 10.0.26100.32313 | 10.0.26100.32313 |
| microsoft | windows_server_2025 | >= 10.0.26100.0 < 10.0.26100.32370 | 10.0.26100.32370 |
CVSS provenance
nvdv3.17.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
vendor_msrc7.3HIGH
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Microsoft
Windows Hyper-V Remote Code Execution Vulnerability
vendor_msrc·2026-02-10·CVSS 7.3
CVE-2026-21248 [HIGH] CWE-122 Windows Hyper-V Remote Code Execution Vulnerability
Windows Hyper-V Remote Code Execution Vulnerability
Description: Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
FAQ: According to the CVSS metric, user interaction is required (UI:R) and privileges required is Low (PR:L). What does that mean for this vulnerability?
The file must be stored in a location that allows an attacker write access, enabling the file to be corrupted. An attacker must send a user a crafted file and convince them to load it.
FAQ: According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). Th
GHSA
GHSA-9h9g-xpmp-46vg: Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally
ghsa_unreviewed·2026-02-10
CVE-2026-21248 [HIGH] CWE-122 GHSA-9h9g-xpmp-46vg: Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally
Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
No detection rules found.
Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos·2026-02-13
February’s Patch Tuesday assumes battle stations
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Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
## Table of Contents
Microsoft Patch Tuesday forFebruary2026
Adobe Patches for February 2026
Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Other Microsoft Vulnerability Highlights
Microsoft Release Summary
Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
Rapid Response with TruRisk Eliminate
Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulnerabilities, i
Bleepingcomputer
Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
blogs_bleepingcomputer·2026-02-10·CVSS 8.8
[HIGH] Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Lawrence Abrams
25 Elevation of Privilege vulnerabilities
5 Security Feature Bypass vulnerabilities
12 Remote Code Execution vulnerabilities
6 Information Disclosure vulnerabilities
3 Denial of Service vulnerabilities
7 Spoofing vulnerabilities
When BleepingComputer reports on Patch Tuesday security updates, we only count those released by Microsoft today. Therefore, the number of flaws does not include 3 Microsoft Edge flaws fixed earlier this month.
As part of these updates, Microsoft has also begun to roll out updated Secure Boot certificates to replace the original 2011 certificates that are expiring in late June 2026.
"With this update, Windows quality updates include a broad set of targeting data that i
Talos
Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-02-10·CVSS 8.8
CVE-2026-21522 [HIGH] Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
## Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February 2026, which includes 59 vulnerabilities affecting a range of products, including two that Microsoft marked as “Critical”.
CVE-2026-21522 is a critical elevation of privilege vulnerability affecting Microsoft ACI Confidential Containers. Successful exploitation of this vulnerability could enable an authorized attacker to escalate privileges on affected systems. This vulnerability is not listed as publicly disclosed and received a CVSS 3.1 score of 6.7.
CVE-2026-23655 is a critical information disclosure vulnerability affecting Microsoft ACI Confidential Containers. This vulnerability could enable an authorized attacker to disclose sensit
Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
#### Table of Contents
- Microsoft Patch Tuesday forFebruary2026
- Adobe Patches for February 2026
- Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Other Microsoft Vulnerability Highlights
- Microsoft Release Summary
- Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
- Rapid Response with TruRisk Eliminate
- Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulner
Talos
Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-02-10·CVSS 8.8
CVE-2026-21522 [HIGH] Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February 2026, which includes 59 vulnerabilities affecting a range of products, including two that Microsoft marked as “Critical”.
CVE-2026-21522 is a critical elevation of privilege vulnerability affecting Microsoft ACI Confidential Containers. Successful exploitation of this vulnerability could enable an authorized attacker to escalate privileges on affected systems. This vulnerability is not listed as publicly disclosed and received a CVSS 3.1 score of 6.7.
CVE-2026-23655 is a critical information disclosure vulnerability affecting Microsoft ACI Confidential Containers. This vulnerability could enable an authorized attacker to disclose sensitive information including secret tokens and keys if successfully exploited. This vulnerabi
Wiz
CVE-2026-21248 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 7.3
CVE-2026-21248 [HIGH] CVE-2026-21248 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-21248 :
vulnerability analysis and mitigation
Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.
Source : NVD
## 7.3
Score
Published February 10, 2026
Severity HIGH
CNA Score 7.3
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 7.6
Exploitation Probability (EPSS) N/A
Sources
NVD
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Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos
February’s Patch Tuesday assumes battle stations
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Microsoft on Tuesday released 58 patches affecting 15 product families. Five of the addressed issues, all involving Azure, are considered by Microsoft to be of Critical severity, though only two require urgent attention (more on that below). Fifteen have a CVSS base score of 8.0 or higher, including two with a 9.8 base score. Six are known to be under active exploit in the wild, and three are publicly disclosed (including one not yet known to be under exploit).
At patch time, five CVEs are judged more likely to be exploited in the next 30 days by the company’s estimation, in addition to the six already detected to be so. Various of this month’s issues are amenable to direct detection by Sophos protections, and we include information on those in a table below. The release also
2026-02-10
Published