CyberSecBulletin
CVE-2026-9740NVD status: Analyzed

MongoDB Server: Uncontrolled Recursion

Published Updated By the CyberSecBulletin desk

CVE-2026-9740 is a high-severity uncontrolled recursion vulnerability in MongoDB Server from MongoDB, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.3.3, 8.2.10, 8.0.24 as the first without the flaw, so updating MongoDB Server to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.34% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update MongoDB Server to 8.3.3 or 8.2.10 or 8.0.24 or 7.0.35, whichever matches your release line, or a later version.
  2. Update Mongodb to 7.0.35 or 8.0.24 or 8.2.10 or 8.3.3, whichever matches your release line, or a later version.
  3. Read the advisory on jira.mongodb.org for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MongoDBMongoDB Server8.3.0 up to, but not including, 8.3.3; 8.2.0 up to, but not including, 8.2.10; 8.0.0 up to, but not including, 8.0.24; 7.0.0 up to, but not including, 7.0.358.3.3, 8.2.10, 8.0.24, 7.0.35
MongoDBMongodb7.0.0 up to, but not including, 7.0.35; 8.0.0 up to, but not including, 8.0.24; 8.2.0 up to, but not including, 8.2.10; 8.3.0 up to, but not including, 8.3.37.0.35, 8.0.24, 8.2.10, 8.3.3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (mongodb.com).

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (mongodb.com)
CVSS 3.17.5HighCNA (mongodb.com)

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Uncontrolled Recursion

The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

How developers prevent this class of flaw

  • Ensure that an end condition will be reached under all logic conditions. The end condition may include checking against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.

More Uncontrolled Recursion vulnerabilities (CWE-674)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in MongoDB Server

All MongoDB Server vulnerabilities

Recent Uncontrolled Recursion vulnerabilities

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