cve/2021/CVE-2021-32040.md

### [CVE-2021-32040](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-32040)
![](https://img.shields.io/static/v1?label=Product&message=MongoDB%20Server&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=4.2%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=4.4%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=5.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-121%20Stack-based%20Buffer%20Overflow&color=brightgreen)

### Description

It may be possible to have an extremely long aggregation pipeline in conjunction with a specific stage/operator and cause a stack overflow due to the size of the stack frames used by that stage. If an attacker could cause such an aggregation to occur, they could maliciously crash MongoDB in a DoS attack. This vulnerability affects MongoDB Server v4.4 versions prior to and including 4.4.28, MongoDB Server v5.0 versions prior to 5.0.4 and MongoDB Server v4.2 versions prior to 4.2.16.Workaround: >= v4.2.16 users and all v4.4 users can add the --setParameter internalPipelineLengthLimit=50 instead of the default 1000 to mongod at startup to prevent a crash.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/11notes/docker-unifi