CVE-2026-18687 Denial of service in MongoDB Server
An authenticated user can cause server crashes and corrupt encrypted index data by submitting malformed requests during Queryable Encryption maintenance operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-18687?
CVE-2026-18687 is a high-severity denial of service vulnerability in Mongodb Mongodb, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
MongoDB Server's handling of a Queryable Encryption maintenance operation did not properly validate certain request parameters against the collection's encrypted field configuration before use. An authenticated user with readWrite privileges could submit a specially formed request that leads to a server crash or excessive internal writes, resulting in resource exhaustion and corruption of encrypted index data.
Weakness: CWE-191
Which versions are affected by CVE-2026-18687?
1 open source package ship an affected version, including mongodb. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mongodb Bitnami | From 8.0.0 | 8.0.29, 8.3.8, 9.0.2 |
Products include Mongodb Mongodb.
How do I fix CVE-2026-18687?
Upgrade mongodb to a fixed version for your release line: 8.0.29, 8.3.8 or 9.0.2.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-18687 being exploited?
There is no known exploitation of CVE-2026-18687 in the wild and no public exploit code.
Other vulnerabilities in Mongodb Mongodb
- CVE-2025-14847 MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency
- CVE-2026-82067 Auth bypass in MongoDB Server
- CVE-2026-13072 MongoDB Improper Input Validation in Compute Mode External Data Processing Leading to Memory Corruption
- CVE-2017-15535 Denial of service in n/a
- CVE-2026-18691 Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
Sources
Also known as BIT-mongodb-2026-18687, GHSA-q4pc-c9m4-c873, MINI-8747-94pj-pxw3, MINI-cc4x-m2c9-xfh5, MINI-ph93-q4vh-p3f4, UBUNTU-CVE-2026-18687.