CVE-2025-21186: microsoft 365_apps Heap-based Buffer Overflow

Vulnerability summary

CVE-2025-21186 is a high (CVSS 7.8) Heap-based Buffer Overflow vulnerability in microsoft 365_apps. EPSS estimates a 1.14% chance of exploitation in the next 30 days, higher than 66.1% of scored vulnerabilities.

Timeline

1. 14-01-2025
   PublishedVulnerability first disclosed.
2. 09-06-2026
   Last modifiedVulnerability information updated.

Description

Microsoft Access Remote Code Execution Vulnerability

• 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().