GitHub Advisoryadvisory · Go

GHSA-rmvv-8v8w-rf7x Mattermost doesn't validate user-supplied input in API request handlers

MEDIUM Published 2026-05-26 Modified 2026-06-29 Official page ↗
Aliases
CVE-2026-4646
Ecosystem
Go
Packages
github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-plugin-github
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weaknesses
CWE-1287
Reviewed
2026-06-29

Affected packages

• Go github.com/mattermost/mattermost-server: >= 11.6.0, < 11.6.1 → fixed in 11.6.1 • Go github.com/mattermost/mattermost-server: >= 11.5.0, < 11.5.4 → fixed in 11.5.4 • Go github.com/mattermost/mattermost-server: >= 11.4.0, < 11.4.5 → fixed in 11.4.5 • Go github.com/mattermost/mattermost-server: >= 10.11.0, < 10.11.15 → fixed in 10.11.15 • Go github.com/mattermost/mattermost-plugin-github: < 1.0.1-0.20260330164815-c2840e980b3c → fixed in 1.0.1-0.20260330164815-c2840e980b3c

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint. Mattermost Advisory ID: MMSA-2026-00638

Related

Alias · CVE (1)

  • CVE-2026-4646 Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API… vulnerability

Weakness · CWE (1)

  • CWE-1287 Improper Validation of Specified Type of Input weakness

References