Mattermost Server 10.5.x <= 10.5.12 / 10.11.x <= 10.11.4 / 10.12.x <= 10.12.1 / 11.0.x <= 11.0.2 Multiple Vulnerabilities (CVE-2025-12421, MMSA-2025-00526, CVE-2025-12756)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(278109);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/26");

  script_cve_id("CVE-2025-12421", "CVE-2025-12559", "CVE-2025-12756");
  script_xref(name:"IAVA", value:"2025-A-0893-S");

  script_name(english:"Mattermost Server 10.5.x <= 10.5.12 / 10.11.x <= 10.11.4 / 10.12.x <= 10.12.1 / 11.0.x <= 11.0.2 Multiple Vulnerabilities (CVE-2025-12421, MMSA-2025-00526, CVE-2025-12756)");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of Mattermost Server installed on the remote host is affected by a vulnerability as referenced in
CVE-2025-12421, MMSA-2025-00526 and CVE-2025-12756.

  - Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12
    fail to to verify that the token used during the code exchange originates from the same 
    authentication flow, which allows an authenticated user to perform account takeover via a 
    specially crafted email address used when switching authentication methods and sending a 
    request to the /users/login/sso/code-exchange endpoint. The vulnerability requires 
    ExperimentalEnableAuthenticationTransfer to be enabled (default: enabled) and 
    RequireEmailVerification to be disabled (default: disabled). (CVE-2025-12421)
  
  - Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12
    fail to sanitize team email addresses to be visible only to Team Admins, which allows any 
    authenticated user to view team email addresses via the 
    GET /api/v4/channels/{channel_id}/common_teams endpoint (CVE-2025-12559)
  
  - Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12
    fail to validate user permissions when deleting comments in Boards, which allows an
    authenticated user with the editor role to delete comments created by other users.
    (CVE-2025-12756)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://mattermost.com/security-updates/");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Mattermost Server version 10.5.13, 10.11.5, 10.12.2, 11.0.3, 11.1.0 or later.");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-12421");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/10/31");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/10/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/12/10");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:mattermost:mattermost_server");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2025-2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("mattermost_server_detect.nbin");
  script_require_keys("installed_sw/Mattermost Server");

  exit(0);
}

include('vcf.inc');
include('http.inc');

var port = get_http_port(default:80);

var app_info = vcf::get_app_info(app:'Mattermost Server', port:port, webapp:true);

var constraints = [
  { 'min_version' : '10.5.0', 'fixed_version' : '10.5.13' },
  { 'min_version' : '10.11.0', 'fixed_version' : '10.11.5' },
  { 'min_version' : '10.12.0', 'fixed_version' : '10.12.2' },
  { 'min_version' : '11.0.0', 'fixed_version' : '11.0.3', 'fixed_display' : '11.0.3 / 11.1.0' }
];

vcf::check_version_and_report(
    app_info:app_info,
    constraints:constraints,
    severity:SECURITY_HOLE
);