CVE-2026-18701Network attack vectorHinoki check available

Authenticated server crash via invalid type conversion

Published Aug 11, 2026 · Updated Aug 11, 2026

Type confusion in MongoDB Server 7.0 before 7.0.40, 8.0 before 8.0.29, and 8.3.0 through 8.3.7 allows remote authenticated users to crash mongod. The expression_tree.cpp serializer static-casts INTERNAL_SCHEMA_MAX_PROPERTIES to PathMatchExpression even though the former is not a descendant of that type. Read privileges suffice: a valid query with a shaped $jsonSchema filter reaches the cast and terminates the server process, interrupting database service.

CVSS severity7.1
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Type confusion in MongoDB Server 7.0 before 7.0.40, 8.0 before 8.0.29, and 8.3.0 through 8.3.7 allows remote authenticated users to crash mongod. The expression_tree.cpp serializer static-casts INTERNAL_SCHEMA_MAX_PROPERTIES to PathMatchExpression even though the former is not a descendant of that type. Read privileges suffice: a valid query with a shaped $jsonSchema filter reaches the cast and terminates the server process, interrupting database service.

The record

CVE
CVE-2026-18701
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-843, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 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 <7.0.40
  2. Affected versionversion=8.0 <8.0.29
  3. Affected versionversion=8.3.0 <8.3.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MongoDB · MongoDB Serverversion=7.0 <7.0.40; version=8.0 <8.0.29; version=8.3.0 <8.3.8

Published CVSS scores

6.5MongoDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1MongoDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1499.004Endpoint Denial of Service: Application 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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