What’s Vulnerable › Vulnerabilities

CVE-2026-114647: NoSQL operator injection via unvalidated replacement document in findOneAndReplace

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-23
• Weakness: CWE-943

Description

The MongoDB C# Driver does not reject replacement documents whose top-level field names begin with a dollar sign in FindOneAndReplace, unlike other replace operations. An application that builds such a document from user-supplied field names can have the server apply update operators instead of a full replacement. The effect is limited to the document matched by the application's own filter, whose contents can be modified in ways the application did not intend.

Affected products

• MongoDB C# Driver: from 2.13.0 before 3.13.0 — fixed in 3.13.0

How to fix

Upgrade to a fixed version: MongoDB C# Driver 3.13.0. Check the vendor advisory for mitigations.

References

• https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0
• https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-68cj-624m-mxj3
• https://jira.mongodb.org/browse/CSHARP-6186

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