CVE-2026-69439ImportantRevised 25 Sep
.NET and Visual Studio Elevation of Privilege Vulnerability
Assessment
Heap-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to elevate privileges over a network.
- Severity
- Important
- CVSS base score
- 8.8CVSS:3.1/
AV:N/ AC:L/ PR:N/ UI:R/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- 0.9%Higher than 56.8% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
- Exploitability
- Exploitation Unlikely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- .NET and Visual Studio
- Weakness
- CWE-122: Heap-based Buffer Overflow
- Issued by
- Microsoft
- Published
- 8 Sep 2026 · September 2026
- Last revised
- 25 Sep 2026Security Updates table updated provide links to the KB articles and download center updates. Microsoft recommends installing the updates.
Updates that fix it
3 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5126104 | Security Update | — | .NET 8.0 installed on Windows | All CVEs in KB5126104 |
| KB5126105 | Security Update | — | .NET 9.0 installed on Windows | All CVEs in KB5126105 |
| KB5126106 | Security Update | — | .NET 10.0 installed on Windows | All CVEs in KB5126106 |
Affected products
Developer Tools6 affected products
- .NET 10.0 installed on Windows
- .NET 11.0 installed on Windows
- .NET 8.0 installed on Windows
- .NET 9.0 installed on Windows
- Microsoft Visual Studio 2022 version 17.14
- Microsoft Visual Studio 2026 version 18.9