MongoBleed Exploit Allows Unauthenticated Attackers to Drain MongoDB Memory - PoC Released

Key Findings

• A critical vulnerability, tracked as CVE-2025-14847, has been discovered in MongoDB, a popular open-source database system.

• The flaw, dubbed "MongoBleed," allows remote, unauthenticated attackers to read sensitive contents from the server's memory (heap), potentially exposing internal states and pointers.

• The vulnerability lies in how MongoDB handles Zlib compressed protocol headers, where the server blindly trusts the length claimed by a client, even when it doesn't match the actual data size.

• A proof-of-concept (PoC) exploit has been published by security researcher Joe Desimone, making it easier for threat actors to target unpatched systems.

• The vulnerability has a CVSS score of 8.7, indicating a high risk to unpatched systems.

• The flaw affects a vast range of MongoDB versions, spanning from modern releases back to legacy systems.

Background

MongoDB is one of the industry's most widely used database systems, with a large and diverse user base. The disclosure of this high-severity vulnerability in MongoDB has created a critical security emergency for database administrators.

Impact

• The MongoBleed vulnerability allows remote, unauthenticated attackers to trick the server into revealing sensitive contents from its memory, potentially exposing internal states and pointers.

• This could lead to the disclosure of sensitive in-memory data, including internal state information, pointers, or other data that may assist an attacker in further exploitation.

• The vulnerability affects a vast range of MongoDB versions, spanning from modern releases back to legacy systems, putting a large number of organizations at risk.

Affected Versions

The vulnerability affects the following MongoDB versions:

• 8.2.0 through 8.2.3

• 8.0.0 through 8.0.16

• 7.0.0 through 7.0.26

• 6.0.0 through 6.0.26

• 5.0.0 through 5.0.31

• 4.4.0 through 4.4.29

• All versions of 4.2, 4.0, and 3.6

Remediation

• MongoDB has released fixed versions to address the vulnerability, with the patched versions being 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, and 4.4.30.

• For organizations that cannot update right away, a workaround exists: disable Zlib by starting the mongod or mongos instances with a net.compression.compressors option that explicitly omits Zlib, opting instead for alternatives like snappy or zstd.

Conclusion

The disclosure of the MongoBleed vulnerability has created a critical security emergency for database administrators. With a proof-of-concept exploit already available, the race is on for defenders to patch their databases before threat actors begin exploiting the flaw and harvesting sensitive data from exposed servers.

Sources

• https://securityonline.info/poc-released-mongobleed-exploit-allows-unauthenticated-attackers-to-drain-mongodb-memory/

• https://x.com/the_yellow_fall/status/2005466439373979890

• https://thecybersecguru.com/exploits/mongobleed-cve-2025-14847-mongodb-zlib/