CVE-2026-8336 Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands
An authenticated user can crash the MongoDB server via a use-after-free error in JavaScript execution commands, causing denial of service.
- 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-2026-8336?
CVE-2026-8336 is a high-severity use after free vulnerability in Mongodb Mongodb, published on 13 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service.
This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.
Weakness: CWE-416
Which versions are affected by CVE-2026-8336?
1 open source package ship an affected version, including mongodb. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mongodb Bitnami | From 8.2.0 | 8.2.9, 8.3.2 |
Products include Mongodb Mongodb.
How do I fix CVE-2026-8336?
Upgrade mongodb to a fixed version for your release line: 8.2.9 or 8.3.2.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-8336 being exploited?
There is no known exploitation of CVE-2026-8336 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-2026-8336, GHSA-5f8r-h2c3-xvqc, MINI-4f9m-h24f-rwp4.