CVE-2026-24458

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

Affected packages (6)

• Go/github.com/mattermost/mattermost-serverfrom 0, < 5.3.2-0.20260129164748-7201f42d955f
• Go/github.com/mattermost/mattermost-server>= 10.11.0-rc1+incompatible, < 10.11.11+incompatible, >= 11.2.0-rc1+incompatible, < 11.2.3+incompatible, >= 11.3.0-rc1+incompatible, < 11.3.1+incompatible
• Go/github.com/mattermost/mattermost-server/v5from 0
• Go/github.com/mattermost/mattermost-server/v6from 0
• Go/github.com/mattermost/mattermost/server/v8from 0, < 8.0.0-20260129164748-7201f42d955f
• Go/github.com/mattermost/mattermost/server/v8from 0, < 8.0.0-20260129164748-7201f42d955f

CVSS scores

References (5)

• ADVISORYhttps://github.com/advisories/GHSA-m5rv-56xx-hfc6
• ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-24458
• PATCHhttps://github.com/mattermost/mattermost
• WEBhttps://github.com/mattermost/mattermost/commit/7201f42d955f1bc44719b862132546626b60a180
• WEBhttps://mattermost.com/security-updates