Connection redirection via percent-encoded delimiter injection in connection string hosts (MongoDB Python Driver)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.36 % · percentile 30 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mongodb
- NVD status
- Awaiting Analysis
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.
Weaknesses (CWE)
- CWE-177 — Improper Handling of URL Encoding (Hex Encoding)
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 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 | mongodb |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N | mongodb |
| CVSS 4.0 | HIGH 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cna@mongodb.com (Secondary) |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N | NVD · cna@mongodb.com (Secondary) |
Advisories
- GHSA-vp6j-j7w5-5xjj — PyMongo: PYTHON-5986 Host injection in PyMongo connection string parsing via percent-encoded delimiters
- PYSEC-2026-4297 — PyMongo: PYTHON-5986 Host injection in PyMongo connection string parsing via percent-encoded delimiters
European references
- ENISA EUVD · EUVD-2026-86347
- GCVE · GCVE-0-2026-96748
CERT-FR advisories
- CERTFR-2026-AVI-1234 — Multiples vulnérabilités dans MongoDB · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| MongoDB · Python Driver | affected 0 < 4.18.2 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |