MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency
CVE-2025-14847 is a high-severity improper handling of length parameter inconsistency vulnerability in MongoDB Server from MongoDB, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.2.3, 8.0.17, 7.0.28 as the first without the flaw, so updating MongoDB Server to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on December 29, 2025, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update MongoDB Server to 8.2.3 or 8.0.17 or 7.0.28 or 6.0.27, whichever matches your release line, or a later version.
- Update Mongodb to 4.4.30 or 5.0.32 or 6.0.27 or 7.0.28, whichever matches your release line, or a later version.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Read the advisory on jira.mongodb.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MongoDB | MongoDB Server | 8.2 up to, but not including, 8.2.3; 8.0 up to, but not including, 8.0.17; 7.0 up to, but not including, 7.0.28; 6.0 up to, but not including, 6.0.27; 5.0 up to, but not including, 5.0.32; 4.4 up to, but not including, 4.4.30; 4.2; 4.0; and 1 more ranges | 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, 4.4.30 |
| MongoDB | Mongodb | 3.6.0 up to, but not including, 4.4.30; 5.0.0 up to, but not including, 5.0.32; 6.0.0 up to, but not including, 6.0.27; 7.0.0 up to, but not including, 7.0.28; 8.0.0 up to, but not including, 8.0.17; 8.2.0 up to, but not including, 8.2.3 | 4.4.30, 5.0.32, 6.0.27, 7.0.28, 8.0.17, 8.2.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (mongodb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (mongodb.com) |
| CVSS 3.1 | 7.5 | High | CNA (mongodb.com) |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Length Parameter Inconsistency
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
How developers prevent this class of flaw
- When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
- Do not let the user control the size of the buffer.
- Validate that the length of the user-supplied data is consistent with the buffer size.
More Improper Handling of Length Parameter Inconsistency vulnerabilities (CWE-130)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- jira.mongodb.org/browse/SERVER-115508Issue Tracking
Third-party and government advisories
- smartkeyss.com/post/mongobleed-pre-auth-memory-disclosure-via-op_compressed-in-mongodb-cve-2025-14847Technical Description, Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-14847Third Party Advisory, US Government Resource
Technical write-ups (may include proof of concept)
- vicarius.io/vsociety/posts/cve-2025-14847-detection-script-heap-memory-exposure-in-mongodb-serverExploit, Third Party Advisory
- vicarius.io/vsociety/posts/cve-2025-14847-mitigation-script-heap-memory-exposure-in-mongodb-serverExploit, Third Party Advisory
Other references
- openwall.com/lists/oss-security/2025/12/29/21Mailing List
Other vulnerabilities in MongoDB Server
- 7.5 High severity
- 8.8 High severity
- 7.1 High severity
- 10.0 Critical severity
- 8.4 High severity
- 7.2 High severity
Recent Improper Handling of Length Parameter Inconsistency vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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