CVE-2026-78439: microsoft microsoft office 365 for mac Stack-based Buffer Overflow

Vulnerability summary

CVE-2026-78439 is a high (CVSS 8.8) Stack-based Buffer Overflow vulnerability in microsoft microsoft office 365 for mac. EPSS estimates a 0.84% chance of exploitation in the next 30 days, higher than 57% of scored vulnerabilities.

Timeline

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

Description

Stack-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.

• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).