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CVE-2026-9740 MongoDB CVE debrief

A vulnerability in MongoDB Server's BSON validation logic allows an unauthenticated user to crash the mongod process by sending a specially crafted message. The BSON validator's handling of certain nested binary data structures permits uncontrolled mutual recursion between validation functions, where each re-entry resets internal depth tracking.

Vendor
MongoDB
Product
MongoDB Server
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-10
Advisory published
2026-06-09
Advisory updated
2026-06-10

Who should care

Users of MongoDB Server are advised to take action.

Technical summary

The vulnerability has a CVSS score of 8.7 and is classified as HIGH severity. It was published on [cvePublishedAt] and last modified on [cveModifiedAt].

Defensive priority

HIGH

Recommended defensive actions

  • Apply the patch or update to the latest version of MongoDB Server.
  • Restrict access to the MongoDB Server to only trusted users.

Evidence notes

The CVE record was obtained from the official CVE website [resourceLinkAnnotations:cve-org]. Additional information was obtained from the NVD detail page [resourceLinkAnnotations:nvd].

Official resources

CVE-2026-9740 was published on 2026-06-09T23:17:03.437Z and last modified on 2026-06-10T19:43:28.857Z.