Vulnerability · Published Oct 22, 2026 · Assigned by mongodb
CVE-2026-114647NoSQL operator injection via unvalidated replacement document in findOneAndReplace
Medium 4.3
In plain English
A medium-severity security flaw in C# Driver from MongoDB. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
Official 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 (as reported)
Weakness: CWE-943 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N