CVE-2026-18697: MongoDB

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

An issue in MongoDB Server's aggregation framework could allow an unauthenticated party to cause a mongos (router) process to terminate unexpectedly by submitting a specially formed aggregation command. This could result in a denial of service, disrupting client connections routed through the affected mongos instance.

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.