CVE-2026-78456: SQL Server Remote Code Execution Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-08 · updated 2026-10-31
Weakness: CWE-122

Description

Heap-based buffer overflow in SQL Server allows an authorized attacker to execute code over a network.

Affected products

Microsoft Sql Server 2022: before 16.0.1200.5; from 16.0.4003.1 before 16.0.4275.2 — fixed in 16.0.1200.5, 16.0.4275.2
Microsoft SQL Server 2022 (CU 26): from 16.0.0.0 before 16.0.4275.2 — fixed in 16.0.4275.2
Microsoft SQL Server 2022 (GDR): from 16.0.0 before 16.0.1200.5 — fixed in 16.0.1200.5

How to fix

Upgrade to a fixed version: Microsoft Sql Server 2022 16.0.1200.5, 16.0.4275.2; Microsoft SQL Server 2022 (CU 26) 16.0.4275.2; Microsoft SQL Server 2022 (GDR) 16.0.1200.5. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78456

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