CVE-2025-14847: Unauthenticated Memory Disclosure Flaw in MongoDB

MongoBleed (CVE-2025-14847) is a severe remote, unauthenticated memory disclosure vulnerability affecting MongoDB servers that use zlib network compression. Disclosed in December 2025, the flaw enables attackers to retrieve sensitive process memory including API keys, authentication tokens, internal URLs, and personal data from affected MongoDB instances without needing authentication. The issue impacts all MongoDB versions from 3.6 onward and poses a significant risk to both cloud-hosted and on-premises deployments that are exposed to the internet.

Severity: High

Vulnerability Details

• CVE ID: CVE-2025-14847
• CVSS Score: 8.7
• Description:
• The vulnerability lies in how MongoDB handles zlib-compressed wire protocol messages.
• When a crafted compressed request specifies an inflated uncompressed size, MongoDB:
  1. Allocates a larger memory buffer than necessary.
  2. Misreports the valid data length after decompression.
  3. Returns residual (uninitialized) heap memory as part of the legitimate response.

Because the zlib decompression logic fails to properly validate buffer lengths, attackers can extract arbitrary portions of memory from the server.
This can occur remotely and without authentication, making it a high-severity, low-complexity exploit.

Affected Versions

MongoDB Version	Vulnerable Builds	Fixed Version	Notes
8.2	8.2.0 – 8.2.2	8.2.3	✅ Patch available
8	8.0.0 – 8.0.16	8.0.17	✅ Patch available
7	7.0.0 – 7.0.27	7.0.28	✅ Patch available
6	6.0.0 – 6.0.26	6.0.27	✅ Patch available
5	5.0.0 – 5.0.31	5.0.32	✅ Patch available
4.4	4.4.0 – 4.4.29	4.4.30	✅ Patch available
4.2 / 4.0 / 3.6	All versions	❌ No fix (EOL)	Must upgrade

Exposure and Attack Surface

Shodan and other scanning platforms reveal tens of thousands of exposed MongoDB instances vulnerable to MongoBleed:

• China: 16,576
• United States: 14,486
• Germany: 11,547
• Hong Kong: 5,521
• Singapore: 4,130

Exposures were also observed in India, Russia, France, Vietnam, and Indonesia.

Proof Of Concept (POC)

A public exploit, mongobleed.py, developed by Joe DeSimone, demonstrates the vulnerability:
python3 mongobleed.py –host –port 27017.
The exploit sends a malformed zlib-compressed message and extracts leaked data into leaked.bin. No authentication or credentials are required.

Impact

MongoBleed can lead to:

• Sensitive Data Disclosure – Leakage of memory containing API keys, credentials, and PII.
• Authentication Bypass – Exploitation without credentials.
• Privilege Escalation – Reuse of tokens for unauthorized access.
• Lateral Movement – Leaked internal service URLs aid internal network pivoting.
• Compliance Violations – Exposed personal data may breach GDPR and PCI-DSS.
• Mass Exploitation Risk – Automated scanning makes widespread exploitation likely.

Recommendations

1. Immediately upgrade to fixed MongoDB versions.
2. EOL versions have no security fixes; immediate migration is mandatory.
3. Use firewalls, security groups, or VPNs to limit access to MongoDB’s default port (27017).
4. Ensure that the database service is not directly reachable from the public internet.
5. If immediate patching is not an option, disable zlib network compression or switch to an alternative compression method to block the exploitation vector.
6. Monitor for malformed compressed requests, abnormal response sizes, and unusual protocol behavior indicative of exploitation attempts.

Source:

• https://www.resecurity.com/blog/article/mongobleed-cve-2025-14847-mongodb-memory-leak-flaw
• https://jira.mongodb.org/browse/SERVER-115508

Enjoyed reading this Threat Intelligence Advisory? Stay updated with our latest exclusive content by following us on Twitter and LinkedIn

No related posts found.