CVE-2026-18709Hinoki check available

Cross-shard inconsistency via unauthorized transaction finalization

Published Aug 11, 2026 · Updated Aug 11, 2026

Missing authorization in MongoDB Server allows remote authenticated users to improperly commit or abort prepared transactions. A shard accepts transaction-finalization operations without enforcing the intended transaction-coordinator authorization; the responsible code locus is undisclosed. Direct shard access and an in-progress prepared transaction are required, and exploitation can corrupt cluster clocks, cross-shard consistency, and atomicity.

CVSS severity5.9
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Missing authorization in MongoDB Server allows remote authenticated users to improperly commit or abort prepared transactions. A shard accepts transaction-finalization operations without enforcing the intended transaction-coordinator authorization; the responsible code locus is undisclosed. Direct shard access and an in-progress prepared transaction are required, and exploitation can corrupt cluster clocks, cross-shard consistency, and atomicity.

The record

CVE
CVE-2026-18709
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-862, T1565.001
Attack vector
adjacent
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 vectoradjacent
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

5.9MongoDB, Inc.CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
6.4MongoDB, Inc.CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:H/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)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.001Stored Data Manipulation

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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