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TI-2026-80468 Aliases CVE-2026-93846GHSA-39rf-335p-gqxg

Team admin can escalate team member permissions in Mattermost

Priority LOW 17CWE-863Published · Updated

Key facts

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

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

Summary

Mattermost versions from 11.7.0 through 11.7.10 do not restrict which built-in roles can be assigned to a team member through the API, which is an incorrect authorization flaw (CWE-863). A team admin can use the team member roles REST API to grant a team member permissions beyond those allowed by the configured permission scheme.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

Mattermost versions 11.7.x <= 11.7.10 fail to restrict which built-in roles can be assigned to a team member via the API, which allows a team admin to grant a team member permissions beyond those permitted by the configured permission scheme via the {{update-team-member-roles}} REST API.. Mattermost Advisory ID: MMSA-2026-00734

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): 11.11.0, 11.7.11

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
MattermostMattermost11.7.0 – 11.7.1011.11.0, 11.7.11Patch availableCNA
  • Mattermost VendorMattermost Affected 11.7.0 – 11.7.10 Fixed in 11.11.0, 11.7.11 Patch available CNA

Remediation

Upgrade Mattermost to version 11.7.11 for the 11.7 line or to version 11.11.0 for later releases, which fix this issue. The vendor advisory is MMSA-2026-00734.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.11.0, 11.7.11

Timeline

  1. 2026-10-26 Threatist record created from CVE-2026-93846
  2. 2026-10-27 Alias added: GHSA-39rf-335p-gqxg
  3. 2026-11-02 CISA SSVC decision points changed

References

Advisory 1

  • TI-2025-18933 Arbitrary file read in Mattermost Boards via import & export board archive CVSS 3.1CRITICAL 9.9
  • TI-2019-15071 An issue was discovered in Mattermost Packages before 5.16.3. CVSS 3.1CRITICAL 9.8
  • TI-2025-04465 Path Traversal Leading to RCE by Any Authenticated Mattermost User CVSS 3.1CRITICAL 9.9
  • TI-2019-15074 An issue was discovered in Mattermost Desktop App before 4.3.0 on macOS. CVSS 3.1CRITICAL 9.8
  • 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
See all 670 →

Sources

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