Heap-based buffer overflow in Microsoft SQL Server - CVE-2026-78456
Published: September 9, 2026
Vulnerability identifier: #VU148421
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-78456
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to a heap-based buffer overflow in SQL Server when processing a specially crafted query or request submitted over a network. A remote user can submit a specially crafted query or request to execute arbitrary code.
User interaction is not required.
Affected software
Microsoft SQL Server
How to mitigate CVE-2026-78456
Install security update from vendor's website.
Microsoft SQL Server - addressed in versions 16.0.1200.5, 16.0.4275.2