Microsoft Visual Studio: Heap-based buffer overflow enables remote code execution
Summary
A heap-based buffer overflow in Microsoft Visual Studio 2026 and the .NET runtime (8.0, 9.0, 10.0 and 11.0 preview) on Windows allows an unauthorized attacker to execute code over the network. The attack requires user interaction, and the exact trigger is not described in the sources. No exploitation or public proof of concept has been reported yet, and NVD analysis is still pending.
Affected
- Microsoft .NET 8.0 on Windows: 8.0.0 to before 8.0.34
- Microsoft .NET 9.0 on Windows: 9.0.0 to before 9.0.23
- Microsoft .NET 10.0 on Windows: 10.0.0 to before 10.0.15
- Microsoft .NET 11.0 on Windows: 11.0.0-preview.1 to before 11.0.0
- Visual Studio 2026 version 18.11: 18.11.0 to before 18.11.4
- Visual Studio 2026 version 18.12: affected, version range not published
Fixed in
- .NET 8.0: 8.0.34 or later (November 2026 servicing update)
- .NET 9.0: 9.0.23 or later (November 2026 servicing update)
- .NET 10.0: 10.0.15 or later (November 2026 servicing update)
- .NET 11.0: 11.0.0 or later
- Visual Studio 2026 version 18.11: 18.11.4 according to a third-party tracker, to be verified on the MSRC page
- Visual Studio 2026 version 18.12: Unknown.
Workaround
Unknown. No vendor workaround identified in the sources. Patching is the stated remedy.
Exploitation
- No evidence of exploitation in the wild found.
- No public proof of concept found.
- CVSS exploit maturity is "Unproven" (E:U).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
Our recommendation
- Inventory all Visual Studio 2026 and .NET 8, 9, 10 and 11 installations on workstations and servers.
- Install the November 2026 updates for Visual Studio and .NET.
- Confirm the fixed Visual Studio build numbers on the MSRC page, especially for version 18.12.
- Until patched, do not open untrusted solutions or projects and do not run untrusted programs on developer workstations.
- Monitor the NVD and MSRC entries for changes in exploitation status.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE record (CNA: Microsoft) www.cve.org
- Microsoft Security Response Center advisory msrc.microsoft.com
- .NET and .NET Framework November 2026 servicing updates devblogs.microsoft.com
- Strix CVE details (third-party, version data unverified) www.strix.ai
- CVE-2026-69439 (related, context only) cvereports.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 10 Nov 2026, 22:43.
Original description (NVD)
Heap-based buffer overflow in Visual Studio allows an unauthorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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