CVE-2025-14847 MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency Vulnerability
MongoDB Server contains an improper handling of length parameter inconsistency vulnerability in Zlib compressed protocol headers. This vulnerability may allow a read of uninitialized heap memory by an unauthenticated client.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 29 Dec 2025.
- Rated High severity (CVSS 7.5, scored by Vendor).
- It has been in the catalogue for 312 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Mismatched length fields in Zlib compressed protocol headers may allow a read of uninitialized heap memory by an unauthenticated client. This issue affects all MongoDB Server v7.0 prior to 7.0.28 versions, MongoDB Server v8.0 versions prior to 8.0.17, MongoDB Server v8.2 versions prior to 8.2.3, MongoDB Server v6.0 versions prior to 6.0.27, MongoDB Server v5.0 versions prior to 5.0.32, MongoDB Server v4.4 versions prior to 4.4.30, MongoDB Server v4.2 versions greater than or equal to 4.2.0, MongoDB Server v4.0 versions greater than or equal to 4.0.0, and MongoDB Server v3.6 versions greater than or equal to 3.6.0.
Affected Versions
| Product | Versions |
|---|---|
| MongoDB Inc. MongoDB Server | 8.2 to before 8.2.3 8.0 to before 8.0.17 7.0 to before 7.0.28 6.0 to before 6.0.27 5.0 to before 5.0.32 4.4 to before 4.4.30 |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for MongoDB and MongoDB Server. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
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