CVE-2026-65674: Insecure Deserialization Flaw in Microsoft SQL Server 2019 (GDR) Scores 8.8 on CVSS
A newly published high vulnerability in Microsoft SQL Server 2019 (GDR) carries a CVSS score of 8.8. Here is what is affected and how to respond.
Key points
- CVE-2026-65674 affects Microsoft SQL Server 2019 (GDR).
- CVSS 8.8 (High).
- No exploitation confirmed yet.
A high insecure deserialization tracked as CVE-2026-65674 has been published in the National Vulnerability Database for Microsoft SQL Server 2019 (GDR), with a CVSS base score of 8.8.
At a glance
- CVE
- CVE-2026-65674
- Product
- Microsoft SQL Server 2019 (GDR)
- CVSS
- 8.8 High
- Weakness
- insecure deserialization
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: Deserialization of untrusted data in SQL Server allows an authorized attacker to execute code over a network.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft SQL Server 2019 (GDR) | before 15.0.2200.2 |
| Microsoft | Microsoft SQL Server 2019 for x64-based Systems (CU32) | before 15.0.4500.2 |
| Microsoft | Microsoft SQL Server 2022 (GDR) | before 16.0.1210.3 |
| Microsoft | Microsoft SQL Server 2022 for x64-based Systems (CU27) | before 16.0.4305.5 |
| Microsoft | Microsoft SQL Server 2025 for x64-based Systems (CU9) | before 17.0.5015.4 |
| Microsoft | Microsoft SQL Server 2025 for x64-based Systems (GDR) | before 17.0.1145.4 |
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C.
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
Background: Insecure deserialization
Look for base64-encoded parameters, unexpected object instantiation, or state changes that bypass authentication. Inspect input handling for unvalidated deserialization. Use allowlists for expected data types and verify integrity with digital signatures to prevent arbitrary code execution.
Read the full guide: Warning Signs of Insecure Deserialization in Web Applications
What to do and how to stay safe: CVE-2026-65674
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-65674?
CVE-2026-65674 is a insecure deserialization vulnerability in Microsoft SQL Server 2019 (GDR).
How severe is CVE-2026-65674?
It has a CVSS score of 8.8 High.
Is CVE-2026-65674 being exploited?
There is no public confirmation of exploitation at the time of publication.
