# CVE-2026-114648: MongoDB C# Driver LINQ field-path injection via unvalidated dictionary keys

Source: https://junglewise.ai/threats/cve-2026-114648-the-mongodb-c-driver-does-not-neutralize-dot-and-dollar  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-22. Updated: 2026-10-22  
License: CC BY 4.0 with a link back

CVE-2026-114648 · Severity: high · CVSS 7.6 · Published 2026-10-22

The MongoDB C# Driver, used by .NET applications to query and update MongoDB databases, fails to validate field names and dictionary keys in LINQ queries. An attacker who controls user input that becomes a field name can silently redirect queries and updates to unintended database fields, exposing other users' data or broadening write operations beyond the intended scope.

Technologies: [MongoDB C Driver](https://junglewise.ai/threats/technologies/c-driver). Vendors: [MongoDB](https://junglewise.ai/threats/vendors/mongodb).

## Quick answers

**Is CVE-2026-114648 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-114648 being exploited in the wild.

**How severe is CVE-2026-114648?** High severity, with a CVSS score of 7.6, published 22 October 2026.

**Which products and versions are affected?** MongoDB C Driver 2.14.0 through 3.12.x.

**Is there a fix for CVE-2026-114648?** Yes: fixed in 3.13.0. Until then: LINQ translation now throws NotSupportedException for dictionary keys, BsonDocument keys, and Mql.Field names that contain dots, start with dollar signs, or use positional operators, preventing silent field-path injection.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-22"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-114648 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-114648?** Check whether you run MongoDB C Driver at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.13.0

LINQ translation now throws NotSupportedException for dictionary keys, BsonDocument keys, and Mql.Field names that contain dots, start with dollar signs, or use positional operators, preventing silent field-path injection.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-22"}]

## Technical details

The vulnerability exists in LINQ translation of dictionary keys, Mql.Field names, and array-filter identifiers that contain dots (.), dollar signs ($), or brackets without validation. These characters are interpreted structurally by MongoDB: dots cause nested field traversal, dollar-prefixed segments trigger operator interpretation, and null identifiers become wildcard array filters. The vulnerable code in AstFilterField.SubField performs raw string concatenation without sanitizing attacker-controlled input before rendering the field path to the wire protocol. An authenticated application user whose input reaches these LINQ positions can perform boolean-oracle attacks on unintended fields and silently broaden update scopes.

## Affected products

- MongoDB C# Driver 2.14.0 through 3.12.x

## References

- [https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0](https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0)
- [https://jira.mongodb.org/browse/CSHARP-6181](https://jira.mongodb.org/browse/CSHARP-6181)

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- [MongoDB C Driver namespace field validation bypass](https://junglewise.ai/threats/cve-2026-120956-the-mongodb-c-driver-does-not-validate-the-type-or-format-of-a)
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