Microsoft SQL Server: Heap-based buffer overflow enables remote code execution
Summary
A heap-based buffer overflow in Microsoft SQL Server allows remote code execution over the network. An attacker needs a valid low-privilege database account, and exploitation is rated as high complexity. A successful attack can fully compromise confidentiality, integrity and availability of the database server, with a changed scope.
Affected
- SQL Server 2017 (GDR): 14.0.0 to below 14.0.2140.2
- SQL Server 2017 for x64-based Systems (CU31): 14.0.3006.16 to below 14.0.3560.2
- SQL Server 2019 (GDR): 15.0.0 to below 15.0.2200.2
- SQL Server 2019 for x64-based Systems (CU32): 15.0.4003.23 to below 15.0.4500.2
- SQL Server 2022 (GDR): 16.0.0 to below 16.0.1210.3
- SQL Server 2022 for x64-based Systems (CU27): 16.0.4003.1 to below 16.0.4305.5
- SQL Server 2025 for x64-based Systems (CU9): 17.0.4006.2 to below 17.0.5015.4
- SQL Server 2025 for x64-based Systems (GDR): 17.0.1050.2 to below 17.0.1145.4 (MSRC table lists a lower bound of 17.0.1000.7; verify your build)
Fixed in
- SQL Server 2017 (GDR): 14.0.2140.2 via KB5128497
- SQL Server 2017 CU31: 14.0.3560.2 (derived from the CVE record; verify against KB5128496)
- SQL Server 2019 (GDR): 15.0.2200.2 via KB5128495
- SQL Server 2019 CU32: 15.0.4500.2 via KB5128494
- SQL Server 2022 (GDR): 16.0.1210.3 via KB5128493
- SQL Server 2022 CU27: 16.0.4305.5 via KB5126934
- SQL Server 2025 CU9: 17.0.5015.4 via KB5126967
- SQL Server 2025 RTM GDR: 17.0.1145.4 via KB5128492
Workaround
No patch-independent workaround or mitigation is documented in the sources. Apply the October 2026 security update for your SQL Server branch.
Exploitation
- No evidence of exploitation in the wild was found.
- Not listed as exploited; EPSS below 1% according to Senserva.
- No known exploits per Tenable; no public proof of concept was found, but the CVE is recent.
Our recommendation
- Patch on-premises SQL Server instances with the October 2026 cumulative update in the next regular maintenance cycle, or sooner if the server is internet-facing.
- Check whether any SQL Server is reachable from the internet and restrict access to application servers and admin networks.
- Review accounts with database access and remove unneeded privileges.
- Patch the whole cumulative update, which also covers CVE-2026-68883 and CVE-2026-88081.
- Monitor for unusual database logins and process activity on database servers.
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 Update Guide: CVE-2026-85886 msrc.microsoft.com
- MSRC advisory table (en-US) msrc.microsoft.com
- KB5128497: SQL Server 2017 October 2026 update support.microsoft.com
- KB5128493: SQL Server 2022 October 2026 update support.microsoft.com
- CVE record summary (threatint) cve.threatint.com
- Strix CVE summary www.strix.ai
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 1 Nov 2026, 10:41.
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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