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TI-2026-03731 Aliases CVE-2026-4286GHSA-gvg4-jhmr-6j23

Playbooks Plugin fails to validate team transfers, allowing unauthorized removal of member access via playbook update

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 · NVD. Fix status from CNA and GitHub. Impact type from CWE-863.

Summary

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to check if {{team_id}} was being changed when updating playbooks, allowing users with only {{Manage Playbook Configurations}} permission to change a playbook's team, bypassing manage members restriction via PUT api. Mattermost Advisory ID: MMSA-2025-00552

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00143 3rd percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.6.0, 11.5.2, 10.11.14github.com/mattermost/mattermost/server/v8 (Go): 11.5.2, 10.11.14+1 more product

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
MattermostMattermost11.5.0 – 11.5.1; 10.11.0 – 10.11.1311.6.0, 11.5.2, 10.11.14Patch availableCNA
—github.com/mattermost/mattermost/server/v8 (Go)11.5.0 to before 11.5.211.5.2Patch availableGHSA-gvg4-jhmr-6j23
—github.com/mattermost/mattermost/server/v8 (Go)10.11.0 to before 10.11.1410.11.14Patch availableGHSA-gvg4-jhmr-6j23
—github.com/mattermost/mattermost-plugin-playbooks (Go)before 1.41.1-0.20260213020129-e1d6ec2c94e61.41.1-0.20260213020129-e1d6ec2c94e6Patch availableGHSA-gvg4-jhmr-6j23
  • Mattermost VendorMattermost Affected 11.5.0 – 11.5.1; 10.11.0 – 10.11.13 Fixed in 11.6.0, 11.5.2, 10.11.14 Patch available CNA
  • github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 11.5.0 to before 11.5.2 Fixed in 11.5.2 Patch available GHSA-gvg4-jhmr-6j23
  • github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 10.11.0 to before 10.11.14 Fixed in 10.11.14 Patch available GHSA-gvg4-jhmr-6j23
  • github.com/mattermost/mattermost-plugin-playbooks (Go) Vendor— Affected before 1.41.1-0.20260213020129-e1d6ec2c94e6 Fixed in 1.41.1-0.20260213020129-e1d6ec2c94e6 Patch available GHSA-gvg4-jhmr-6j23

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*10.11.0 to before 10.11.14; 11.5.0 to before 11.5.2VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.14; 11.5.0 to before 11.5.2 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.6.0, 11.5.2, 10.11.14
  • Fix · GHSA-gvg4-jhmr-6j23 github.com/mattermost/mattermost/server/v8 (Go) Fixed in 11.5.2 Advisory →
  • Fix · GHSA-gvg4-jhmr-6j23 github.com/mattermost/mattermost/server/v8 (Go) Fixed in 10.11.14 Advisory →
  • Fix · GHSA-gvg4-jhmr-6j23 github.com/mattermost/mattermost-plugin-playbooks (Go) Fixed in 1.41.1-0.20260213020129-e1d6ec2c94e6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-4286
  2. 2026-10-03 Alias added: GHSA-gvg4-jhmr-6j23

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