CVE-2026-88166: microsoft microsoft sharepoint server subscription edition Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-88166 is a high (CVSS 8.8) Integer Overflow or Wraparound vulnerability in microsoft microsoft sharepoint server subscription edition. EPSS estimates a 0.82% chance of exploitation in the next 30 days, higher than 56.7% of scored vulnerabilities.

Timeline

1. 13-10-2026
   PublishedVulnerability first disclosed.
2. 21-10-2026
   Last modifiedVulnerability information updated.

Description

Integer overflow or wraparound in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

• 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.
• 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).