A type allow-list bypass in the BSON serialization library of the MongoDB C# Driver allows a type-restriction check to be circumvented when polymorphic data is deserialized into loosely typed members. An unauthorized party who can supply or plant BSON/JSON data that the application later deserializes can cause the application process to instantiate .NET types outside the intended allow-list and populate them with unauthorized party-controlled values. In applications that contain a suitable gadget type, this can lead to arbitrary code execution in the context of the application, with corresponding loss of confidentiality, integrity, and availability. No special privileges beyond the ability to introduce data the application reads are required.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
| Link | Providers |
|---|---|
| https://jira.mongodb.org/browse/CSHARP-6160 |
|
History
Fri, 13 Nov 2026 00:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A type allow-list bypass in the BSON serialization library of the MongoDB C# Driver allows a type-restriction check to be circumvented when polymorphic data is deserialized into loosely typed members. An unauthorized party who can supply or plant BSON/JSON data that the application later deserializes can cause the application process to instantiate .NET types outside the intended allow-list and populate them with unauthorized party-controlled values. In applications that contain a suitable gadget type, this can lead to arbitrary code execution in the context of the application, with corresponding loss of confidentiality, integrity, and availability. No special privileges beyond the ability to introduce data the application reads are required. | |
| Title | Remote code execution via generic-type allow-list bypass in BSON object deserialization | |
| Weaknesses | CWE-502 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: mongodb
Published:
Updated: 2026-11-13T00:00:12.446Z
Reserved: 2026-11-12T04:02:06.614Z
Link: CVE-2026-126982
No data.
Status : Received
Published: 2026-11-13T00:20:13.250
Modified: 2026-11-13T00:20:13.250
Link: CVE-2026-126982
No data.
OpenCVE Enrichment
No data.
Weaknesses