Medium · published September 8, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| mongodb/mongodb | ≥ 7.0.0, < 7.0.41 | 7.0.41 |
| mongodb/mongodb | ≥ 8.0.0, < 8.0.30 | 8.0.30 |
| mongodb/mongodb | ≥ 8.3.0, < 8.3.9 | 8.3.9 |