Read the docs
TI-2026-21260 Aliases CVE-2026-26304GHSA-4pmx-622h-x359

Permission Bypass in Playbook Run Creation

Priority LOW 19CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.

Summary

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00169 6th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.4.0, 11.3.1, 11.2.3github.com/mattermost/mattermost-plugin-playbooks (Go): 1.41.1-0.20260316224925-705f54a81841

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MattermostMattermost11.3.0 – 11.3.0; 11.2.0 – 11.2.211.4.0, 11.3.1, 11.2.3Patch availableCNA
—github.com/mattermost/mattermost-plugin-playbooks (Go)before 1.41.1-0.20260316224925-705f54a818411.41.1-0.20260316224925-705f54a81841Patch availableGHSA-4pmx-622h-x359
  • Mattermost VendorMattermost Affected 11.3.0 – 11.3.0; 11.2.0 – 11.2.2 Fixed in 11.4.0, 11.3.1, 11.2.3 Patch available CNA
  • github.com/mattermost/mattermost-plugin-playbooks (Go) Vendor— Affected before 1.41.1-0.20260316224925-705f54a81841 Fixed in 1.41.1-0.20260316224925-705f54a81841 Patch available GHSA-4pmx-622h-x359

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*11.2.0 to before 11.2.3; 11.3.0 to before 11.3.1VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 11.2.0 to before 11.2.3; 11.3.0 to before 11.3.1 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.4.0, 11.3.1, 11.2.3
  • Fix · GHSA-4pmx-622h-x359 github.com/mattermost/mattermost-plugin-playbooks (Go) Fixed in 1.41.1-0.20260316224925-705f54a81841 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26304
  2. 2026-10-03 Alias added: GHSA-4pmx-622h-x359

References

Advisory 2

Other 2

  • TI-2025-18933 Arbitrary file read in Mattermost Boards via import & export board archive CVSS 3.1CRITICAL 9.9
  • TI-2025-04465 Path Traversal Leading to RCE by Any Authenticated Mattermost User CVSS 3.1CRITICAL 9.9
  • TI-2017-14068 An issue was discovered in Mattermost Server before 3.6.2. CVSS 3.1CRITICAL 9.8
  • TI-2017-14060 An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. CVSS 3.1CRITICAL 9.8
  • TI-2017-14048 An issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. CVSS 3.1CRITICAL 9.8
  • TI-2025-14360 Arbitrary file read via block duplication in Mattermost Boards CVSS 3.1CRITICAL 9.9
See all 505 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences