CVE-2024-42406Network attack vector

Archived-channel data disclosure via missing authorization checks

Published Sep 26, 2024 · Updated Sep 26, 2024

Improper access control in affected Mattermost 9.x releases allows remote authenticated users to retrieve archived-channel post and file data. Affected API4 handlers return flagged or unread posts and file metadata without enforcing the disabled archived-channel visibility setting. A normal authenticated account and a deployment with archived-channel viewing disabled are required; exposure is limited to posts and files the setting should hide.

CVSS severity5.4
Medium
EPSS probability0.22%
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 affected Mattermost 9.x releases allows remote authenticated users to retrieve archived-channel post and file data. Affected API4 handlers return flagged or unread posts and file metadata without enforcing the disabled archived-channel visibility setting. A normal authenticated account and a deployment with archived-channel viewing disabled are required; exposure is limited to posts and files the setting should hide.

The record

CVE
CVE-2024-42406
Published
Sep 26, 2024
Updated
Sep 26, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-284, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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=9.10.0 <=9.10.1
  2. Affected versionversion=9.11.0
  3. Affected versionversion=9.5.0 <=9.5.8
  4. Affected versionversion=9.9.0 <=9.9.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=9.10.0 <=9.10.1; version=9.11.0; version=9.5.0 <=9.5.8; version=9.9.0 <=9.9.2

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
5.4Mattermost, Inc.CVSS: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.

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-284Improper Access Control
T1190Exploit Public-Facing Application

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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