Full Report
A high-severity security flaw has been disclosed in MongoDB that could allow unauthenticated users to read uninitialized heap memory. The vulnerability, tracked as CVE-2025-14847 (CVSS score: 8.7), has been described as a case of improper handling of length parameter inconsistency, which arises when a program fails to appropriately tackle scenarios where a length field is inconsistent with the
Analysis Summary
# Vulnerability: Unauthenticated Heap Memory Read in MongoDB via Zlib Protocol Flaw
## CVE Details
- CVE ID: CVE-2025-14847
- CVSS Score: 8.7 (High)
- CWE: Improper Handling of Length Parameter Inconsistency (Related to CWE-130)
## Affected Systems
- Products: MongoDB Server
- Versions:
- v8.2.0 through 8.2.3
- v8.0.0 through 8.0.16
- v7.0.0 through 7.0.26
- v6.0.0 through 6.0.26
- v5.0.0 through 5.0.31
- v4.4.0 through 4.4.29
- All v4.2 versions
- All v4.0 versions
- All v3.6 versions
- Configurations: Systems utilizing the Zlib compressed protocol headers for network communication.
## Vulnerability Description
This high-severity flaw is rooted in the **improper handling of length parameter inconsistency** within the Zlib compressed protocol headers used in MongoDB's network communication. An unauthenticated client-side exploit can improperly interact with the decompression logic, causing the MongoDB server to mistakenly read and return **uninitialized heap memory**. This memory dump could expose sensitive in-memory data, internal state information, pointers, or other data valuable for further exploitation.
## Exploitation
- Status: No explicit mention of "in the wild," but PoC trigger mentioned via client-side exploit. **PoC available** (implied by threat actor capability).
- Complexity: Low (Can be triggered by an unauthenticated network client).
- Attack Vector: Network
## Impact
- Confidentiality: **High** (Disclosure of internal heap memory contents).
- Integrity: Low (Memory read, not direct modification).
- Availability: Low (Memory read generally does not cause a crash, though memory disclosure could facilitate subsequent attacks).
## Remediation
### Patches
Users must upgrade to one of the fixed versions:
- MongoDB 8.2.3 or later
- MongoDB 8.0.17 or later
- MongoDB 7.0.28 or later
- MongoDB 6.0.27 or later
- MongoDB 5.0.32 or later
- MongoDB 4.4.30 or later
### Workarounds
If immediate updating is not possible, disable zlib compression on the MongoDB Server:
1. Start `mongod` or `mongos` using the `--networkMessageCompressors` option, explicitly omitting `zlib`.
2. Alternatively, configure the `net.compression.compressors` option to omit `zlib`. (Other supported compressors are `snappy` and `zstd`).
## Detection
- Indicators of Compromise: Observation of unusually large, potentially random data payloads returned from the MongoDB server in response to protocol interaction, originating from unauthenticated source IPs.
- Detection Methods and Tools: Network monitoring or intrusion detection systems capable of inspecting application-layer protocol exchanges between clients and the MongoDB server may detect unusual communication patterns associated with the Zlib compression negotiation phase.
## References
- Vendor Advisory (SERVER Ticket Reference): [jira.mongodb.org/browse/SERVER-115508](https://jira.mongodb.org/browse/SERVER-115508) (Defanged)
- CVE Record: [cve.org/CVERecord?id=CVE-2025-14847](https://www.cve.org/CVERecord?id=CVE-2025-14847) (Defanged)
- Security Research/Analysis: [op-c.net/blog/mongodb-zlib-protocol-vulnerability-cve-2025-14847](https://op-c.net/blog/mongodb-zlib-protocol-vulnerability-cve-2025-14847) (Defanged)