CVE-2024-24776Network attack vector

Channel member-count disclosure via missing permission check

Published Feb 9, 2024 · Updated Aug 1, 2024

Improper access control in Mattermost 8.1.7 and earlier and 9.4.0 allows remote authenticated users to read channel member counts. The POST /api/v4/channels/stats/member_count handler aggregates roles across requested channels instead of requiring read permission for each channel. A low-privileged account can infer membership size for channels it cannot read, but no message contents or modification capability are exposed.

CVSS severity3.1
Low
EPSS probability0.31%
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 8.1.7 and earlier and 9.4.0 allows remote authenticated users to read channel member counts. The POST /api/v4/channels/stats/member_count handler aggregates roles across requested channels instead of requiring read permission for each channel. A low-privileged account can infer membership size for channels it cannot read, but no message contents or modification capability are exposed.

The record

CVE
CVE-2024-24776
Published
Feb 9, 2024
Updated
Aug 1, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-284
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 9, 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=0 <=8.1.7
  2. Affected versionversion=9.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=8.1.7; version=9.4.0

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
2.3GitHubCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
3.1Mattermost, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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

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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