CVE-2025-3446Network attack vector

Guest addition via incorrect team invite permission check

Published May 15, 2025 · Updated May 15, 2025

Incorrect authorization in Mattermost allows remote authenticated users to add guest users to teams through the single-user team API. The endpoint checks permission to invite non-guest users instead of guest-invite permission before adding the supplied user to a team. An account allowed to invite ordinary members but denied guest invitations can cross the intended role boundary in 9.11.0 through 9.11.11, 10.4.0 through 10.4.4, 10.5.0 through 10.5.2, and 10.6.0 through 10.6.1.

CVSS severity4.3
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Mattermost allows remote authenticated users to add guest users to teams through the single-user team API. The endpoint checks permission to invite non-guest users instead of guest-invite permission before adding the supplied user to a team. An account allowed to invite ordinary members but denied guest invitations can cross the intended role boundary in 9.11.0 through 9.11.11, 10.4.0 through 10.4.4, 10.5.0 through 10.5.2, and 10.6.0 through 10.6.1.

The record

CVE
CVE-2025-3446
Published
May 15, 2025
Updated
May 15, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-863, T1098
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 15, 2025CVE publishedPublication date reported by the CVE source.
  2. May 15, 2025Record 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=10.4.0 <=10.4.4
  2. Affected versionversion=10.5.0 <=10.5.2
  3. Affected versionversion=10.6.0 <=10.6.1
  4. Affected versionversion=9.11.0 <=9.11.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.4.0 <=10.4.4; version=10.5.0 <=10.5.2; version=10.6.0 <=10.6.1; version=9.11.0 <=9.11.11

Published CVSS scores

4.3GitHub Advisory DatabaseCVSS: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

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Your stack

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