Connection redirection via percent-encoded delimiter injection in connection string hosts
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- Low · High · None
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| MongoDB | Python Driver | before 4.18.2 | 4.18.2 | Patch available | CNA |
| — | pymongo (PyPI) | 3.5.0 to before 4.18.2 | 4.18.2 | Patch available | GHSA-vp6j-j7w5-5xjj |
- Python Driver VendorMongoDB Affected before 4.18.2 Fixed in 4.18.2 Patch available CNA
- pymongo (PyPI) Vendor— Affected 3.5.0 to before 4.18.2 Fixed in 4.18.2 Patch available GHSA-vp6j-j7w5-5xjj
Remediation
- Fix · CNA Python Driver (MongoDB) Fixed in 4.18.2
- Fix · GHSA-vp6j-j7w5-5xjj pymongo (PyPI) Fixed in 4.18.2 Advisory →
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
MongoDB Python Driver 4.18.2
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-63846 Heap out-of-bounds write via signed size overflow in BSON document encodingPriority LOW 34
- TI-2026-63844 Forced local Unix socket connection via dot-sock KMS endpoint in client-side field encryptionPriority LOW 23
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 13 (Queens) | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 16.2 | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 17.1 | Affected | No fix planned: Out of support scope |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-96748
- 2026-10-06 Alias added: GHSA-vp6j-j7w5-5xjj
- 2026-10-06 Fix available: PyPI/[email protected] · GHSA-vp6j-j7w5-5xjj
- 2026-10-06 CVSS score added · GHSA-vp6j-j7w5-5xjj
- 2026-10-06 Weakness changed · GHSA-vp6j-j7w5-5xjj
- 2026-10-06 9 new references · GHSA-vp6j-j7w5-5xjj
References
Other 8
- 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
- https://github.com/mongodb/mongo-python-driver/pull/3066
- https://github.com/mongodb/mongo-python-driver/commit/1e7a56db4649b14c4c9a6ac20aa4a8d0d1bb238a
- https://github.com/mongodb/mongo-python-driver/commit/640dd2383a1a2fb1a10e5222d50ebc0b22a61bd7
- https://github.com/mongodb/mongo-python-driver
- https://www.mongodb.com/community/forums/t/pymongo-4-18-2-released/343732
More MongoDB vulnerabilities
- TI-2019-08023 Code injection in mongo-express KEVCVSS 3.1CRITICAL 9.9
- TI-2025-13542 Zlib compressed protocol header length confusion may allow memory read KEVCVSS 4.0HIGH 8.7
- TI-2026-79432 BSON output corruption via out-of-range binary subtype in MongoDB C# Driver CVSS 4.0MEDIUM 6.9
- TI-2026-79424 NoSQL command injection via mismatched BSON length in MongoDB C# Driver CVSS 4.0MEDIUM 6.9
- TI-2026-79422 Unbounded memory growth in MongoDB C# Driver BSON deserialization CVSS 4.0HIGH 8.2
- TI-2026-79427 Authentication bypass via issuer-and-serial-only certificate equality CVSS 4.0HIGH 7.6
Sources
- CVE-2026-96748 · CVE Program
- CVE-2026-96748 · NVD
- FIRST EPSS
- GHSA-vp6j-j7w5-5xjj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-96748 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences