Microsoft SQL Server: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft SQL Server allows an authorized attacker to execute code over the network. The attacker needs a valid low-privilege login and no user interaction is required. The CVE record lists SQL Server 2025 CU10 and SQL Server 2025 GDR (x64) builds as affected, but the Microsoft advisory could not be retrieved, so the scope is not yet confirmed.
Affected
- Microsoft SQL Server 2025 CU10: 17.0.4006.0 to below 17.0.5045.3 (per CVE record)
- Microsoft SQL Server 2025 for x64-based Systems (GDR): 17.0.1050.2 to below 17.0.1155.3 (per CVE record)
Fixed in
Unknown. Confirm the fixed builds in the Microsoft Security Update Guide advisory for CVE-2026-67646.
Workaround
Unknown. No vendor workaround has been confirmed for this CVE.
Exploitation
- No known exploitation in the wild at the time of writing.
- No public proof of concept found.
- Not listed in the CISA KEV catalogue.
Our recommendation
- Inventory all SQL Server instances and their builds, and identify any that are network-exposed.
- Compare the builds with the affected ranges above and check the Microsoft advisory for the fixed build.
- Apply the Microsoft update once it is confirmed to include CVE-2026-67646.
- Restrict network access to SQL Server to trusted segments and limit which accounts can log in.
- Monitor for unusual SQL Server activity and re-check the advisory and CISA KEV for changes.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-67646 msrc.microsoft.com
- Microsoft Security Update Guide: CVE-2026-67642 (sibling advisory, context only) msrc.microsoft.com
- Microsoft KB5122769: SQL Server 2025 CU8, September 2026 support.microsoft.com
- Microsoft KB5122770: SQL Server 2025 GDR, September 2026 support.microsoft.com
- Microsoft KB5122771: SQL Server 2022 GDR, September 2026 support.microsoft.com
- Microsoft KB5128492: SQL Server 2025 GDR, October 2026 support.microsoft.com
- Microsoft KB5128493: SQL Server 2022 GDR, October 2026 support.microsoft.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, 21:02.
Original description (NVD)
Heap-based buffer overflow in SQL Server allows an authorized 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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