CVE-2025-12559Network attack vector

Authenticated team-email disclosure via unsanitized API response

Published Nov 27, 2025 · Updated Nov 28, 2025

Information disclosure in affected Mattermost Server releases allows remote authenticated users to read team email addresses through an API request. The common-teams handler serialized raw Team objects without calling App.SanitizeTeams, leaving Email fields populated for callers lacking PermissionManageTeam. Any authenticated channel user could reach the endpoint and disclose team addresses, while the documented impact excludes modification and service interruption.

CVSS severity4.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in affected Mattermost Server releases allows remote authenticated users to read team email addresses through an API request. The common-teams handler serialized raw Team objects without calling App.SanitizeTeams, leaving Email fields populated for callers lacking PermissionManageTeam. Any authenticated channel user could reach the endpoint and disclose team addresses, while the documented impact excludes modification and service interruption.

The record

CVE
CVE-2025-12559
Published
Nov 27, 2025
Updated
Nov 28, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-200, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 28, 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=10.11.0 <=10.11.4
  2. Affected versionversion=10.12.0 <=10.12.1
  3. Affected versionversion=10.5.0 <=10.5.12
  4. Affected versionversion=11.0.0 <=11.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.4; version=10.12.0 <=10.12.1; version=10.5.0 <=10.5.12; version=11.0.0 <=11.0.2

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/AC:L/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 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-200Exposure of Sensitive Information to an Unauthorized Actor
T1213Data from Information Repositories

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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