Critical MongoDB Vulnerability Exposes Sensitive Data via Zlib Compression

A critical security vulnerability, tracked as CVE-2025-14847, that could allow attackers to extract uninitialized heap memory from database servers without authentication.

The flaw resides in MongoDB’s zlib compression implementation and affects multiple versions of the database platform.​

The vulnerability enables client-side exploitation of the MongoDB Server’s zlib implementation. Potentially exposing sensitive data stored in uninitialized heap memory.

What makes this flaw particularly dangerous is that attackers can exploit it without authenticating to the server, significantly lowering the barrier for malicious actors.​

The vulnerability impacts a wide range of MongoDB versions, spanning several major releases:​

Product	Affected Versions
MongoDB	8.2.0 through 8.2.2
MongoDB	8.0.0 through 8.0.16
MongoDB	7.0.0 through 7.0.26
MongoDB	6.0.0 through 6.0.26
MongoDB	5.0.0 through 5.0.31
MongoDB	4.4.0 through 4.4.29
MongoDB	All versions of 4.2
MongoDB	All versions of 4.0
MongoDB	All versions of 3.6

MongoDB strongly recommends upgrading to the patched versions  8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, or 4.4.30.​

For organizations that cannot upgrade immediately, MongoDB recommends a temporary workaround.

Disable zlib compression by configuring mongod or mongos to omit zlib in the networkMessageCompressors or net. Compression/compressor settings: Use safe alternatives such as Snappy or Zstd, or turn off compression.

Exposing uninitialized heap memory can lead to information disclosure. Potentially revealing sensitive database contents, cryptographic keys, or other confidential data residing in server memory.

Security teams should prioritize patching MongoDB installations immediately to prevent potential data breaches.

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