NoSQL command injection via mismatched BSON length in MongoDB C# Driver
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
The MongoDB C# Driver does not check that the size declared inside raw or lazy BSON data matches the amount of data supplied, and it copies that data onto the wire unchanged. An unauthenticated party who can supply binary content to an affected application can insert or remove elements in the database command the application issues (CWE-130), without database credentials. This can lead to unauthorized modification of stored data and disclosure of data beyond the application's intended request, limited by the database privileges the application holds.
Written with Claude Haiku 5.5 from the sources below · 2026-11-02
Description from the CNA
A data-validation flaw exists in the BSON handling and binary serialization path of the MongoDB C# Driver. When an application constructs a raw or lazy BSON document object from externally supplied binary data, the driver does not verify that the size quantity declared inside that data matches the amount of data actually provided, and it copies the data onto the wire unchanged. An unauthenticated party who can supply binary content to such an application can thereby cause additional elements to be inserted into, or existing elements to be removed from, the database command the application issues, without needing any database credentials of their own. This can result in unauthorized modification of stored data and disclosure of data outside the intended scope of the application's request, bounded by the database privileges the application itself holds.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade MongoDB C# Driver from 2.0.0 before 3.13.0 to version 3.13.0.
Written with Claude Haiku 5.5 from the sources below · 2026-11-02
- Fix · CNA C# Driver (MongoDB) Fixed in 3.13.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
MongoDB C# Driver 3.13.0
11 records Highest priority Priority HIGH 5 HIGH, 6 MEDIUM
Other records, highest priority first
- TI-2026-79432 BSON output corruption via out-of-range binary subtype in MongoDB C# DriverPriority HIGH 70
- TI-2026-79422 Unbounded memory growth in MongoDB C# Driver BSON deserializationPriority HIGH 69
- TI-2026-79427 Authentication bypass via issuer-and-serial-only certificate equalityPriority HIGH 68
Timeline
- 2026-10-22 Threatist record created from CVE-2026-114646
- 2026-10-23 1 new reference · CNA
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-11-02 CISA SSVC decision points changed
- 2026-11-02 Priority changed: LOW → HIGH
References
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-2026-79422 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
- TI-2026-79426 NoSQL injection in MongoDB C# Driver LINQ filter field names CVSS 4.0HIGH 7.2
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences