Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-m5rv-56xx-hfc6 Mattermost fails to properly handle very long passwords
Fixes

Solution

Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher.


Workaround

No workaround given by the vendor.

References
History

Wed, 18 Mar 2026 18:15:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost
Mattermost mattermost Server

Mon, 16 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 16 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587
Title DoS attack via login attempts with multi-megabyte passwords
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-03-16T13:49:55.523Z

Reserved: 2026-02-13T10:01:31.942Z

Link: CVE-2026-24458

cve-icon Vulnrichment

Updated: 2026-03-16T13:43:41.984Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-16T14:18:16.573

Modified: 2026-03-18T18:14:11.770

Link: CVE-2026-24458

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses