CVE-2025-3227Network attack vector

Unauthorized channel membership changes via playbook participants

Published Jun 20, 2025 · Updated Jun 23, 2025

Incorrect authorization in affected Mattermost releases allows remote authenticated users to add or remove public and private channel members. Playbook participant updates fail to enforce Manage Channel Members permission before synchronizing participants with a linked channel. Any authenticated user who can manipulate a channel-linked playbook run can change channel access despite lacking the channel-management permission.

CVSS severity4.3
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Incorrect authorization in affected Mattermost releases allows remote authenticated users to add or remove public and private channel members. Playbook participant updates fail to enforce Manage Channel Members permission before synchronizing participants with a linked channel. Any authenticated user who can manipulate a channel-linked playbook run can change channel access despite lacking the channel-management permission.

The record

CVE
CVE-2025-3227
Published
Jun 20, 2025
Updated
Jun 23, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-863, T1098
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.5.0 <=10.5.5
  2. Affected versionversion=10.6.0 <=10.6.5
  3. Affected versionversion=10.7.0 <=10.7.2
  4. Affected versionversion=10.8.0
  5. Affected versionversion=9.11.0 <=9.11.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.5.0 <=10.5.5; version=10.6.0 <=10.6.5; version=10.7.0 <=10.7.2; version=10.8.0; version=9.11.0 <=9.11.15

Published CVSS scores

4.3MattermostCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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-863Incorrect Authorization
T1098Account 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo