CVE-2026-18695Network attack vector

Authenticated server crash via invalid $jsonSchema predicate

Published Aug 11, 2026 · Updated Aug 11, 2026

Reachable assertion in MongoDB Server 7.0, 8.0, and 8.3 allows remote authenticated users with write access to crash mongod. An update against a time-series collection with a metaField accepts an array as the $jsonSchema predicate, and query processing reaches a fatal assertion instead of rejecting the invalid schema. The attacker must be able to write the affected collection; successful exploitation terminates the server process and interrupts database service.

CVSS severity7.1
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in MongoDB Server 7.0, 8.0, and 8.3 allows remote authenticated users with write access to crash mongod. An update against a time-series collection with a metaField accepts an array as the $jsonSchema predicate, and query processing reaches a fatal assertion instead of rejecting the invalid schema. The attacker must be able to write the affected collection; successful exploitation terminates the server process and interrupts database service.

The record

CVE
CVE-2026-18695
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-617, 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

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
6.5MongoDBCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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