CVE-2026-9740Network attack vector

Pre-authentication crash via recursive BSON validation

Published Jun 9, 2026 · Updated Jun 9, 2026

Uncontrolled recursion in MongoDB Server allows remote attackers to crash the mongod process with a crafted BSON message. The BSON validator permits mutual recursion between nested-binary validation functions because each re-entry resets internal depth tracking. No authentication or user interaction is required; affected releases are 7.0.0 through 7.0.34, 8.0.0 through 8.0.23, 8.2.0 through 8.2.9, and 8.3.0 through 8.3.2, and successful exploitation interrupts database service.

CVSS severity8.7
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in MongoDB Server allows remote attackers to crash the mongod process with a crafted BSON message. The BSON validator permits mutual recursion between nested-binary validation functions because each re-entry resets internal depth tracking. No authentication or user interaction is required; affected releases are 7.0.0 through 7.0.34, 8.0.0 through 8.0.23, 8.2.0 through 8.2.9, and 8.3.0 through 8.3.2, and successful exploitation interrupts database service.

The record

CVE
CVE-2026-9740
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-674, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.0.0 <7.0.35
  2. Affected versionversion=8.0.0 <8.0.24
  3. Affected versionversion=8.2.0 <8.2.10
  4. Affected versionversion=8.3.0 <8.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MongoDB · MongoDB Serverversion=7.0.0 <7.0.35; version=8.0.0 <8.0.24; version=8.2.0 <8.2.10; version=8.3.0 <8.3.3

Published CVSS scores

8.7MongoDB, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5MongoDB, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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