Encrypted fields stored in plaintext by MongoDB C# Driver
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
The affected packages are the MongoDB C# Driver from 2.10.0 before 3.13.0 and the MongoDB.Libmongocrypt NuGet package from 1.0.0 through 1.12.0. Under certain platform text-encoding configurations, an internal name conversion loses information (CWE-838), so client-side encryption does not match its configured rules and the operation proceeds without encryption and without an error. An application user who can write data through an affected application can have sensitive fields persisted in plaintext.
Written with Claude Haiku 5.5 from the sources below · 2026-11-02
Description from the CNA
A flaw in the client-side encryption support of the MongoDB .NET/C# driver can cause data designated for client-side field-level encryption to be written without encryption. Under certain platform text-encoding configurations, an internal name conversion loses information, so the encryption layer fails to associate the operation with its configured encryption rules and the operation proceeds without an error being raised. An application user with the ability to write data through an affected application can therefore have sensitive fields persisted in plaintext, defeating the confidentiality guarantee that client-side encryption is intended to provide. No integrity or availability impact was observed.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- 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
Remediation
Upgrade the MongoDB C# Driver to version 3.13.0. The sources list no fixed version for MongoDB.Libmongocrypt NuGet package.
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-2026-79424 NoSQL command injection via mismatched BSON length in MongoDB C# DriverPriority HIGH 70
- TI-2026-79422 Unbounded memory growth in MongoDB C# Driver BSON deserializationPriority HIGH 69
Timeline
- 2026-10-22 Threatist record created from CVE-2026-114650
- 2026-10-23 Affected versions changed · CNA
- 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 → MEDIUM
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-2026-79424 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
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences