CVE-2026-96748

high

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.

References

https://github.com/mongodb/mongo-python-driver/security/advisories/GHSA-vp6j-j7w5-5xjj

https://github.com/mongodb/mongo-python-driver/releases/tag/4.18.2

https://github.com/mongodb/mongo-python-driver/blob/4.18.2/doc/changelog.rst

Details

Source: Mitre, NVD

Published: 2026-09-24

Updated: 2026-09-24

Risk Information

CVSS v2

Base Score: 6.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:C/A:N

Severity: Medium

CVSS v3

Base Score: 6.5

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

Severity: Medium

CVSS v4

Base 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

Severity: High