CVE-2026-55026: microsoft 365_apps Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-55026 is a medium (CVSS 6.2) Integer Overflow or Wraparound vulnerability in microsoft 365_apps. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.6% of scored vulnerabilities.

Timeline

1. 14-07-2026
   PublishedVulnerability first disclosed.
2. 08-10-2026
   Last modifiedVulnerability information updated.

Description

Integer overflow or wraparound in Microsoft Office allows an unauthorized attacker to disclose information locally.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.