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.
History

Fri, 25 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-140
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 25 Sep 2026 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb python Driver
Vendors & Products Mongodb
Mongodb python Driver

Thu, 24 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
References
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 24 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Connection redirection via percent-encoded delimiter injection in connection string hosts
Weaknesses CWE-177
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N'}

cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: mongodb

Published: 2026-09-24T18:18:12.032Z

Updated: 2026-09-24T19:12:05.362Z

Reserved: 2026-09-23T15:45:50.867Z

Link: CVE-2026-96748

cve-icon Vulnrichment

Updated: 2026-09-24T18:36:33.745Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-24T19:17:20.813

Modified: 2026-09-24T21:00:46.893

Link: CVE-2026-96748

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-24T18:18:12Z

Links: CVE-2026-96748 - Bugzilla