CVE-2026-96748: Connection redirection via percent-encoded delimiter injection in connection string hosts
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.
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N · CWE-177
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
MongoDB: Python Driver
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/mongodb/mongo-python-driver/blob/4.18.2/doc/changelog.rst (opens in new tab)
- github.com/mongodb/mongo-python-driver/releases/tag/4.18.2 (opens in new tab)
- github.com/mongodb/mongo-python-driver/security/advisories/GHSA-vp6j-j7w5-5xjj (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)