MongoBleed: 87,000 MongoDB Servers Leaking Memory Like Heartbleed
You trust your database to keep your data safe. MongoDB just proved it doesn’t. 87,000 servers are leaking memory to anyone who asks. 😏
December 2025. CVE-2025-14847, rated CVSS 8.7, nicknamed “MongoBleed” because it works exactly like Heartbleed did eleven years ago.
Zlib compression is enabled by default in MongoDB. When a compressed message arrives, the server reads a header claiming how large the data will be after decompression. MongoDB allocates that amount of memory, decompresses the payload, and sends back the response.








