Improper Handling of URL Encoding (Hex Encoding) in mongo-python-driver - CVE-2026-96748
Published: September 24, 2026
Vulnerability identifier: #VU151938
CSH Severity: Medium
CVSS v4: 8.3 [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-ID: CVE-2026-96748
CWE-ID: CWE-177
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose credentials or route operations to an attacker-controlled server.
The vulnerability exists due to improper handling of URL encoding in PyMongo connection string host parsing when processing connection strings containing untrusted host input. A remote attacker can supply a hostname fragment containing percent-encoded delimiters to inject an attacker-controlled host and port into the client's seed list.
Unix domain socket paths are not affected.
Affected software
mongo-python-driver
How to mitigate CVE-2026-96748
Install security update from vendor's website.
mongo-python-driver - update to 4.18.2