CVE-2024-39837Network attack vector

Unauthorized arbitrary channel creation

Published Aug 1, 2024 · Updated Aug 1, 2024

Improper access control in Mattermost 9.5.0 through 9.5.6 and 9.9.0 allows remote attackers to create arbitrary channels through Shared Channels. Mattermost has not published the code-level locus or the specific authorization check omitted during remote channel creation. Reachability requires Shared Channels and a trusted remote connection under high-privilege control; the reported consequence is unauthorized channel creation.

CVSS severity3.8
Low
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Mattermost 9.5.0 through 9.5.6 and 9.9.0 allows remote attackers to create arbitrary channels through Shared Channels. Mattermost has not published the code-level locus or the specific authorization check omitted during remote channel creation. Reachability requires Shared Channels and a trusted remote connection under high-privilege control; the reported consequence is unauthorized channel creation.

The record

CVE
CVE-2024-39837
Published
Aug 1, 2024
Updated
Aug 1, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-284
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record 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=9.5.0 <=9.5.6
  2. Affected versionversion=9.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Mattermost · Mattermostversion=9.5.0 <=9.5.6; version=9.9.0

Published CVSS scores

3.8Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A: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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control

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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