CVE-2026-96748
Published:September 24, 2026
Updated:October 09, 2026
PyMongo's connection string parsing decodes percent-encoded characters in the host portion before the host list is separated on its delimiters. When an application places a hostname value supplied by an unauthenticated party into a connection string, that party may cause additional servers of their choosing to be added to the application's database client. The application may then send its authentication exchange and database operations to one of those servers, which can observe limited information and return altered results.
Affected Packages
pymongo (CONDA):
Affected version(s) >=3.2.2 <4.18.2Fix Suggestion:
Update to version 4.18.2pymongo (CONDA):
Affected version(s) >=3.6.1 <4.18.2Fix Suggestion:
Update to version 4.18.2https://github.com/mongodb/mongo-python-driver.git (GITHUB):
Affected version(s) >=3.1rc0 <4.18.2Fix Suggestion:
Update to version 4.18.2pymongo (PYTHON):
Affected version(s) >=3.5.0 <4.18.2Fix Suggestion:
Update to version 4.18.2pymongo (PYTHON):
Affected version(s) >=3.1 <4.18.2Fix Suggestion:
Update to version 4.18.2Related Resources (10)
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Contact UsCVSS v4
Base Score:
8.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Handling of URL Encoding (Hex Encoding)
EPSS
Base Score:
0.26