PT-2026-42404 · Mattermost · Mattermost

0X7Oda7123 · Published 2026-05-21 · Updated 2026-06-25 · CVE-2026-4055

Positive Technologies (AI Summary)

CVSS v3.1

4.3

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Mattermost version 11.5.1

Description An issue exists where the system fails to validate the team-level run create permission against the target team during the creation of a playbook run. This allows an authenticated team member to create runs in teams where they lack the necessary permissions by specifying a different team ID in the run creation API request.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

Incorrect Authorization

Weakness Enumeration

CWE-863

Related Identifiers

BDU:2026-09268

CVE-2026-4055

GHSA-6CFR-WP44-6QMV

GO-2026-5173

Affected Products

Mattermost

References · 12

• https://osv.dev/vulnerability/GHSA-6cfr-wp44-6qmv · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-5173 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-4055 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-09268 · Security Note
• https://github.com/mattermost/mattermost · Note
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-4055 · Note
• https://twitter.com/CVEnew/status/2057407791053037971 · Twitter Post
• https://t.me/CVEtracker/54468 · Telegram Post
• https://github.com/advisories/GHSA-6cfr-wp44-6qmv · Note
• https://dbugs.ptsecurity.com/vulnerability/PT-2026-42404 · Note
• https://twitter.com/infoflowcloud/status/2057408736679940573 · Twitter Post