CVE-2026-24458 PUBLISHED

DoS attack via login attempts with multi-megabyte passwords

Assigner: Mattermost
Reserved: 13.02.2026 Published: 16.03.2026 Updated: 16.03.2026

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

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.3.0 to 11.3.0 (incl.) affected from 11.2.0 to 11.2.2 (incl.) affected from 10.11.0 to 10.11.10 (incl.) Version 11.4.0 is unaffected Version 11.3.1 is unaffected Version 11.2.3 is unaffected Version 10.11.11 is unaffected

Solutions

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

Credits

winfunc finder

References

MMSA-2026-00587

Problem Types

CWE-770: Allocation of Resources Without Limits or Throttling CWE