CVE-2026-18688: MongoDB

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

An issue in MongoDB Server's aggregation framework could allow an authenticated user to trigger an out-of-bounds memory read by providing a specially formed numeric parameter in a certain aggregation pipeline stage. This could result in a server crash (denial of service) and may potentially expose a limited amount of memory contents.

Affected products

• MongoDB MongoDB: from 7.0.0, before 7.0.40 (fixed in 7.0.40); from 8.0.0, before 8.0.29 (fixed in 8.0.29); from 8.2.0, up to and including 8.2.12; from 8.3.0, before 8.3.8 (fixed in 8.3.8); version 9.0.0 only; version 9.1.0 only

Published 2026-08-11. Last modified 2026-09-16.