CVE-2026-9749Network attack vector

Authenticated server crash via stale exchange watermark

Published Jun 9, 2026 · Updated Jun 9, 2026

Reachable assertion in affected MongoDB Server releases allows remote authenticated users to crash the server through a crafted aggregation pipeline. The internal $exchange stage fails to update a key range's high watermark after its per-consumer buffer fills under key-range partitioning with ordered delivery. Affected versions 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; authentication and a skewed result distribution are required.

CVSS severity7.1
High
EPSS probability0.27%
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 affected MongoDB Server releases allows remote authenticated users to crash the server through a crafted aggregation pipeline. The internal $exchange stage fails to update a key range's high watermark after its per-consumer buffer fills under key-range partitioning with ordered delivery. Affected versions 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; authentication and a skewed result distribution are required.

The record

CVE
CVE-2026-9749
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
authenticated

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 privilegesauthenticated

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

6.5MongoDB, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1MongoDB, Inc.CVSS: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.

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.

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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