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

8.2 highEPSS 0.2%

High (8.2) in mongodb mongodb server. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.

On this page
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.

Severity

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

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
EPSS
0.2% estimated probability of exploitation activity in the next 30 days; 8th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-436 Interpretation Conflict
OWASP Top 10
A06:2025 Insecure Design
Published
Modified
Assigned by
mongodb (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

  • mongodb:mongodb server

Versions

From the CNA's record in the CVE List.

ProductAffected
MongoDB Serverfrom 9.0.0 before 9.0.7
MongoDB Serverfrom 8.3.0 before 8.3.16
MongoDB Serverfrom 8.0.0 before 8.0.37
MongoDB Serverfrom 7.0.0 before 7.0.48

Attack patterns (CAPEC)

  • CAPEC-34 HTTP Response Splitting Likelihood: Medium · Severity: High
  • CAPEC-105 HTTP Request Splitting Likelihood: Medium · Severity: High
  • CAPEC-273 HTTP Response Smuggling Likelihood: Medium · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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