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TI-2026-03510 Aliases CVE-2026-4055GHSA-6cfr-wp44-6qmv

Insufficient permission validation on cross-team 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 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API request. Mattermost Advisory ID: MMSA-2026-00629

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00152 4th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.6.0, 11.5.2, 10.11.14 +1github.com/mattermost/mattermost/server/v8 (Go): 8.0.0-20260320113102-f2b3d1c6a945

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 – 11.5.111.6.0, 11.5.2, 10.11.14, 11.4.4Patch availableCNA
—github.com/mattermost/mattermost/server/v8 (Go)8.0.0-20260304132957-9f2616376582 to before 8.0.0-20260320113102-f2b3d1c6a9458.0.0-20260320113102-f2b3d1c6a945Patch availableGHSA-6cfr-wp44-6qmv
  • Mattermost VendorMattermost Affected 11.5.0 – 11.5.1 Fixed in 11.6.0, 11.5.2, 10.11.14, 11.4.4 Patch available CNA
  • github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 8.0.0-20260304132957-9f2616376582 to before 8.0.0-20260320113102-f2b3d1c6a945 Fixed in 8.0.0-20260320113102-f2b3d1c6a945 Patch available GHSA-6cfr-wp44-6qmv

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*10.11.0 to before 10.11.17; 11.5.0 to before 11.5.5; 11.6.0 to before 11.6.2VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.17; 11.5.0 to before 11.5.5; 11.6.0 to before 11.6.2 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.6.0, 11.5.2, 10.11.14, 11.4.4
  • Fix · GHSA-6cfr-wp44-6qmv github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20260320113102-f2b3d1c6a945 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-4055
  2. 2026-10-03 Alias added: GHSA-6cfr-wp44-6qmv

References

Advisory 2

Other 1

  • 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