A recently disclosed security vulnerability in MongoDB has come under active exploitation in the wild, with over 87,000 potentially susceptible instances identified across the world.
The vulnerability in question is CVE-2025-14847 (CVSS score: 8.7), which allows an unauthenticated attacker to remotely leak sensitive data from the MongoDB server memory. It has been codenamed MongoBleed.
"A flaw in zlib compression allows attackers to trigger information leakage," OX Security said. "By sending malformed network packets, an attacker can extract fragments of private data."
The problem is rooted in MongoDB Server's zlib message decompression implementation ("message_compressor_zlib.cpp"). It affects instances with zlib compression enabled, which is the default configuration. Successful exploitation of the shortcoming could allow an attacker to extract sensitive information from MongoDB servers, including user information, passwords, and API keys.
"Although the attacker might need to send a large amount of requests to gather the full database, and some data might be meaningless, the more time an attacker has, the more information could be gathered," OX Security added.
Cloud security company Wiz said CVE-2025-14847 stems from a flaw in the zlib-based network message decompression logic, enabling an unauthenticated attacker to send malformed, compressed network packets to trigger the vulnerability and access uninitialized heap memory without valid credentials or user interaction.
