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PatchSiren cyber security CVE debrief

CVE-2026-9742 MongoDB CVE debrief

CVE-2026-9742 is a high-severity vulnerability with a CVSS score of 8.2. When OIDC authentication is enabled, clients can set specific values in the 'mechanism' parameter of the 'authenticate' command, causing a server crash. This command is accessible to unauthenticated clients, leading to potential pre-auth denial-of-service in affected product configurations. The CVE was published on [cvePublishedAt](https://www.cve.org/CVERecord?id=CVE-2026-9742) and last modified on [cveModifiedAt](https://nvd.nist.gov/vuln/detail/CVE-2026-9742).

Vendor
MongoDB
Product
MongoDB Server
CVSS
HIGH 8.2
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

Security teams and administrators of systems using OIDC authentication should be aware of this vulnerability and assess their configurations for potential exposure.

Technical summary

The vulnerability allows unauthenticated clients to cause a server crash by manipulating the 'mechanism' parameter in the 'authenticate' command when OIDC authentication is enabled.

Defensive priority

High

Recommended defensive actions

  • Review and update configurations to ensure OIDC authentication is properly secured.
  • Monitor systems for unusual 'authenticate' command activity.
  • Apply patches or mitigations provided by the vendor once available.

Evidence notes

The vendor is currently listed as 'Unknown Vendor', but evidence suggests a potential link to MongoDB.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-9742 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-9742

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

  • CVE-2026-9742 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-9742

    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.