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

Status: published. Published: 2026-10-22. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- MongoDB / C# Driver: ≥ 2.13.0; < 3.13.0 (affected, semver). Source: CNA: mongodb

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: mongodb

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N; source: CNA: mongodb

- CISA KEV: No listing in collected sources

- EPSS: 0.26% as of 2026-11-01; percentile 17.59%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-943

## Exploit evidence

- exploit: https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-68cj-624m-mxj3 (ADP: CISA-ADP)

## References

- https://jira.mongodb.org/browse/CSHARP-6186 (CNA: mongodb)

- https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0 (CNA: mongodb)

- https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-68cj-624m-mxj3 (CNA: mongodb)

- https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-68cj-624m-mxj3 (ADP: CISA-ADP; exploit)

## Provenance

- CNA: mongodb: https://www.cve.org/CVERecord?id=CVE-2026-114647; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-114647; retrieved 2026-11-02; source updated Not reported

Revision: b051fbfda5290b44daee280be143ffd601cb96062650c062659a68496b456299

Canonical: https://y2.dev/cve/CVE-2026-114647