CVE-2026-96299: mongodb mongodb server Reachable Assertion

Vulnerability summary

CVE-2026-96299 is a high (CVSS 7.1) Reachable Assertion vulnerability in mongodb mongodb server. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 13.4% of scored vulnerabilities.

Timeline

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

Description

A security issue was discovered in MongoDB mongos (the sharded cluster router) where an authenticated user with readWrite privileges could crash the mongos process by crafting a specially formed aggregation pipeline. The issue leverages an internal aggregation stage that lacks proper authorization checks despite being intended for internal use, allowing a subsequent stage to be forced to execute on the router under conditions it was not designed to handle. This results in an unhandled fatal error that causes the mongos process to immediately abort, resulting in denial of service for all clients routed through the affected mongos instance.

• CWE-617Reachable AssertionThe product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.