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HIGH · CVSS 7.5 CISA Known Exploited Vulnerability

CVE-2025-14847

MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency Vulnerability

MongoDB and MongoDB Server

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.

CVSS
7.5
HIGH
EPSS
83.2%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
19 Dec 2025
CWE-130

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 29 December 2025. US federal agencies were required to remediate it by 19 January 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 83.2%, which is higher than 99.7% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Frequently asked questions

Is CVE-2025-14847 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2025-14847.

What does CVE-2025-14847 affect?

CVE-2025-14847 affects MongoDB and MongoDB Server. 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.

How severe is CVE-2025-14847?

CVE-2025-14847 is rated HIGH with a CVSS base score of 7.5. EPSS puts the probability of exploitation in the next 30 days at 83.2%, higher than 99.7% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 19 January 2026.

How should organisations respond to CVE-2025-14847?

Apply the vendor patch for MongoDB and MongoDB Server as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.