# CVE-2026-120813: Plaintext storage of encrypted fields via duplicate keys in client-side encryption schema parsing

Status: published. Published: 2026-11-10. Updated: 2026-11-13.

An issue in MongoDB Server's client-side field-level encryption (CSFLE) schema processing component allows encryption metadata to be silently dropped during schema parsing under certain conditions. A party who can deliver a specially crafted schema to a user's CSFLE client may cause sensitive data intended for encryption to be stored in plaintext, bypassing confidentiality protections. Exploitation requires the ability to deliver the malicious schema to the user's client, such as through a man-in-the-middle position or an untrusted server.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- MongoDB / MongoDB Server: ≥ 9.0.0; < 9.0.7 (affected, semver); ≥ 8.3.0; < 8.3.16 (affected, semver); ≥ 8.0.0; < 8.0.37 (affected, semver); ≥ 7.0.0; < 7.0.48 (affected, semver). Source: CNA: mongodb

## Severity and prioritization

- CVSS 4.0: 8.2 (high); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: mongodb

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N; source: CNA: mongodb

- CVSS 4.0: 8.2 (high); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: cna@mongodb.com

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N; source: NVD: cna@mongodb.com

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-13; percentile 7.58%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-436

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://jira.mongodb.org/browse/SERVER-132517 (CNA: mongodb)

- https://jira.mongodb.org/browse/SERVER-132517 (cna@mongodb.com)

## Provenance

- CNA: mongodb: https://www.cve.org/CVERecord?id=CVE-2026-120813; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-120813; retrieved 2026-11-11; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-120813; retrieved 2026-11-13; source updated Not reported

Revision: 8d374818ec0e4ac88c67fc06a9cde8bb3d7ee77c0a75ce3c9a8ec9eb5f34b5fb

Canonical: https://y2.dev/cve/CVE-2026-120813

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