MongoBleed Memory Leak
Find Threat Talks on
Inside the MongoBleed Memory Leak
Your memory just became the attack surface. Attackers didn’t need to crack passwords, there was no complex exploit chain. They simply abused normal protocol behavior, over and over again.
That’s MongoBleed, also known as CVE-2025-14847.
Each abused protocol request leaks a little more MongoDB memory until something valuable shows up, even in environments that already follow network segmentation best practices.
In this episode of Threat Talks, Rob Maas, Field CTO at ON2IT, speaks with Luca Cipriano, CTI and Red Team Program Lead, about what MongoBleed reveals about exposure at the database layer.
MongoDB is everywhere: cloud platforms, scalable applications, and data-heavy environments where availability matters more than friction. That makes understanding how this vulnerability works relevant for anyone responsible for running or securing MongoDB instances, even in environments that already follow network segmentation best practices.
What you’ll learn
- How MongoBleed enables an unauthenticated MongoDB memory leak
Why memory allocation before authentication allows data to be exposed without credentials. - How MongoDB’s wire protocol and compressed messages are abused
What happens when declared message sizes influence memory allocation. - Why repetition turns small memory leaks into real exposure
How repeated requests can gradually leak credentials, API keys, or other sensitive data. - What CVE-2025-14847 reveals about MongoDB exposure in practice
Why reachability matters in cloud environments, even when network segmentation best practices are in place.
Your cybersecurity experts
Rob Maas
Field CTO
ON2IT
Luca Cipriano
Red Team & Cyber Threat Intelligence Program Lead
ON2IT
Episode details
The MongoBleed vulnerability, tracked as CVE-2025-14847, allows attackers to extract fragments of MongoDB memory without authenticating by abusing how the database handles compressed wire protocol messages. No credentials are required. No complex exploit chain is involved. Repetition is enough.
In this episode, Rob Maas and Luca Cipriano break down how MongoDB processes compressed messages on its wire protocol and why declared message sizes matter. By sending messages that claim to decompress into much larger payloads than they actually contain, MongoDB allocates more memory than needed before verifying the content of the message.
Because this memory is not always cleared, previously used data can remain present. When BSON strings are parsed without proper termination, MongoDB continues reading memory until it encounters a null byte. The resulting error messages can include fragments of memory that were never intended to be exposed.
This behavior becomes significant through repetition. A single request may reveal nothing useful. Repeated requests, however, can gradually leak credentials, API keys, or other sensitive information. The episode explains why this class of vulnerability is often referred to as a “bleed” and how MongoBleed fits that pattern.
Rather than focusing on theory, the episode highlights why reachability matters and why vulnerabilities like MongoBleed are easy to underestimate.
Get your Hacker T-shirt
Join the treasure hunt!
Find the code within this episode and receive your own hacker t-shirt for free.
