Vulnerability · Published Sep 8, 2026 · Assigned by mongodb
CVE-2026-82059Improper Access Restriction of Internal Aggregation Expression in MongoDB Server Leads to Assertion Failure and Denial of Service
Medium 5.3
In plain English
A medium-severity security flaw in MongoDB Server from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official description
An internal aggregation expression in MongoDB Server was incorrectly registered as accessible to any authenticated user rather than being restricted to internal cluster operations. By crafting a malformed index specification within this expression, an authenticated user with read-only privileges could trigger an assertion failure in the index key generation code path. In certain build configurations, this assertion failure results in termination of the mongod process, causing a denial of service to all connected clients.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | MongoDB Server | 8.3.0 – before 8.3.98.0.0 – before 8.0.307.0.0 – before 7.0.41 |
Weakness: CWE-617 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H