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Vulnerabilities

Vulnerability · CVE-2026-9740

A vulnerability in MongoDB Server's BSON validation logic allows an unauthenticated user to crash the mongod process by sending a specially crafted message.

Published Jun 9, 2026 · catalog updated Jul 23, 2026 · A vulnerability in MongoDB

Last checked Nov 1, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-9740. EPSS is 0.34%. Act only if a listed version of A vulnerability in MongoDB is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A vulnerability in MongoDB).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.34%
Remediation
Version ranges on file
Affected products
cpe mongodb/mongodb

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe mongodb/mongodb< 7.0.35
  • cpe mongodb/mongodb< 8.0.24
  • cpe mongodb/mongodb< 8.2.10
  • cpe mongodb/mongodb< 8.3.3

How to fix CVE-2026-9740

  • Upgrade

    CVE-2026-9740 lists a fix boundary at 7.0.35. Compare the installed build with that boundary before you change production.

  • Version check

    Affected < 7.0.35

  • Advisory

    Open the inventory_high record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-9740. EPSS is 0.34%. Act only if a listed version of A vulnerability in MongoDB is installed.

Which versions are affected?

Compare what you have installed with < 7.0.35, < 8.0.24, < 8.2.10, < 8.3.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-674. EPSS 0.34%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

MongoDB security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 9, 2026 · Monitored products — high

    Detected

    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.

  2. Jul 23, 2026 · Monitored products — high

    Updated

    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.

Sources

  • Monitored products — highVendor advisoryCVE-2026-9740

    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.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 1, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Monitored products — highNov 1, 2026