Microsoft SQL Server: Remote code execution via heap-based buffer overflow
Summary
Multiple supported versions of Microsoft SQL Server (2017, 2019, 2022 and 2025) contain a heap-based buffer overflow. An authorized attacker can exploit it over the network to execute code. CVSS 8.8 (High) assumes low privileges and no user interaction. CISA SSVC rates the technical impact as total, but exploitation is not automatable.
Affected
- SQL Server 2017 (GDR): 14.0.0 before 14.0.2140.2
- SQL Server 2017 x64 (CU31): 14.0.3006.16 before 14.0.3560.2
- SQL Server 2019 (GDR): 15.0.0 before 15.0.2200.2
- SQL Server 2019 x64 (CU32): 15.0.4003.23 before 15.0.4500.2
- SQL Server 2022 (GDR): 16.0.0 before 16.0.1210.3
- SQL Server 2022 x64 (CU27): 16.0.4003.1 before 16.0.4305.5
- SQL Server 2025 x64 (CU9): 17.0.4006.2 before 17.0.5015.4
- SQL Server 2025 x64 (GDR): 17.0.1050.2 before 17.0.1145.4
Fixed in
- SQL Server 2017 GDR: 14.0.2140.2 (KB5128497)
- SQL Server 2017 CU31: 14.0.3560.2 (KB5128496)
- SQL Server 2019 GDR: 15.0.2200.2 (KB5128495)
- SQL Server 2019 CU32: 15.0.4500.2 (KB5128494)
- SQL Server 2022 GDR: 16.0.1210.3 (KB5128493)
- SQL Server 2022 CU27 and GDR1: 16.0.4305.5 (KB5126934)
- SQL Server 2025 CU9 and GDR: 17.0.5015.4 (KB5126967)
- SQL Server 2025 RTM GDR: 17.0.1145.4 (KB5128492)
No fixed build for SQL Server 2016 or older is listed in the sources.
Workaround
Unknown. No mitigation specific to this vulnerability was found. Apply the security update.
Exploitation
- No exploitation in the wild found.
- No public proof of concept found.
- CISA SSVC: exploitation none, not automatable, total technical impact.
Our recommendation
- Install the October 2026 security update for each affected SQL Server branch as soon as possible.
- Verify the build numbers against the Microsoft KB pages before rollout, because some are taken from secondary sources.
- Do not expose SQL Server directly to the internet, and block TCP 1433 and other SQL ports at the perimeter.
- Restrict SQL logins to least privilege and disable unused accounts.
- Monitor for unusual logins and service crashes.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-94512 msrc.microsoft.com
- Microsoft KB5128495: SQL Server 2019 GDR, October 2026 support.microsoft.com
- Microsoft KB5128492: SQL Server 2025 GDR, October 2026 support.microsoft.com
- Microsoft KB5128494: SQL Server 2019 CU32 GDR, October 2026 support.microsoft.com
- Senserva: KB5126934 summary senserva.com
- Threatint: CVE-2026-94512 cve.threatint.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 31 Oct 2026, 17:07.
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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