Unauthenticated heap-memory disclosure via zlib length mismatch
Published Dec 19, 2025 · Updated Dec 19, 2025
Information disclosure in MongoDB Server allows remote attackers to read uninitialized heap memory before authentication via a compressed request. The zlib decompressor reports the allocated output-buffer length instead of the actual decompressed length, so message handling treats unwritten heap bytes as valid response data. Exploitation requires zlib protocol compression to be enabled and yields memory disclosure only, without reported data modification or service interruption.
Summary
What happened
Information disclosure in MongoDB Server allows remote attackers to read uninitialized heap memory before authentication via a compressed request. The zlib decompressor reports the allocated output-buffer length instead of the actual decompressed length, so message handling treats unwritten heap bytes as valid response data. Exploitation requires zlib protocol compression to be enabled and yields memory disclosure only, without reported data modification or service interruption.
The record
- CVE
- CVE-2025-14847
- Published
- Dec 19, 2025
- Updated
- Dec 19, 2025
- Vendor
- MongoDB
- Product
- MongoDB Server
- Classifications
- CWE-130, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 19, 2025CVE publishedPublication date reported by the CVE source.
- Dec 19, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.6
- Affected versionversion=4.0
- Affected versionversion=4.2
- Affected versionversion=4.4 <4.4.30
- Affected versionversion=5.0 <5.0.32
- Affected versionversion=6.0 <6.0.27
- Affected versionversion=7.0 <7.0.28
- Affected versionversion=8.0 <8.0.17
- Affected versionversion=8.2 <8.2.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- mongobleed.py memory-leak exploitfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog listingknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
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