CVE-2026-67631: microsoft microsoft sql server 2017 (cu 31) Heap-based Buffer Overflow

Vulnerability summary

CVE-2026-67631 is a critical (CVSS 9.8) Heap-based Buffer Overflow vulnerability in microsoft microsoft sql server 2017 (cu 31). EPSS estimates a 0.97% chance of exploitation in the next 30 days, higher than 61.4% of scored vulnerabilities.

Timeline

1. 08-09-2026
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

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

• CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().