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CVE-2026-9741 MongoDB CVE debrief

CVE-2026-9741 is a HIGH severity vulnerability in MongoDB's query analysis processing of the $vectorSearch aggregation stage for Queryable Encryption (QE) or Client-Side Field Level Encryption (CSFLE). A bug in this process results in literal values for encrypted fields within the $vectorSearch stage filter expressions to be sent to the server as plaintext instead of ciphertext. This issue was published on [2026-06-09T23:17:03.583Z](cve-org) and last modified on [2026-06-10T19:43:28.857Z](cve-org).

Vendor
MongoDB
Product
MongoDB Server
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-18
Advisory published
2026-06-09
Advisory updated
2026-06-18

Who should care

Users of MongoDB's Queryable Encryption (QE) or Client-Side Field Level Encryption (CSFLE) features should be aware of this vulnerability. The CVSS score for this vulnerability is 7.1, indicating a HIGH severity level.

Technical summary

The vulnerability is caused by a bug in the query analysis processing of the $vectorSearch aggregation stage. This bug causes literal values for encrypted fields within the $vectorSearch stage filter expressions to be sent to the server as plaintext instead of ciphertext.

Defensive priority

HIGH

Recommended defensive actions

  • Review and apply patches or updates provided by MongoDB to address this vulnerability.
  • Implement additional monitoring and logging to detect potential exploitation attempts.

Evidence notes

The CVE record [CVE-2026-9741 CVE record](cve-org) and NVD detail [CVE-2026-9741 NVD detail](nvd) provide further information about this vulnerability. A source reference [Source reference](ref-4) is also available.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-9741 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-9741

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-9741 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-9741

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.