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TI-2025-10797 Aliases CVE-2025-11777GHSA-mqcj-8c2g-h97q

Cross-team channel membership access

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
Low · None · 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 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00196 9th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.0.0, 10.11.4, 10.5.12github.com/mattermost/mattermost-server (Go): 10.11.4, 10.5.12, 5.3.2-0.20250905150616-ba86dfc5876b+4 more products

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
MattermostMattermost10.11.0 – 10.11.3; 10.5.0 – 10.5.1111.0.0, 10.11.4, 10.5.12Patch availableCNA
—github.com/mattermost/mattermost-server (Go)10.11.0 to before 10.11.410.11.4Patch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost-server (Go)10.5.0 to before 10.5.1210.5.12Patch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost/server/v8 (Go)before 8.0.0-20250905150616-ba86dfc5876b8.0.0-20250905150616-ba86dfc5876bPatch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost (Go)before 5.3.2-0.20250905150616-ba86dfc5876b5.3.2-0.20250905150616-ba86dfc5876bPatch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost-server (Go)before 5.3.2-0.20250905150616-ba86dfc5876b5.3.2-0.20250905150616-ba86dfc5876bPatch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost-server/v5 (Go)before 5.3.2-0.20250905150616-ba86dfc5876b5.3.2-0.20250905150616-ba86dfc5876bPatch availableGHSA-mqcj-8c2g-h97q
—github.com/mattermost/mattermost-server/v6 (Go)before 5.3.2-0.20250905150616-ba86dfc5876b5.3.2-0.20250905150616-ba86dfc5876bPatch availableGHSA-mqcj-8c2g-h97q
  • Mattermost VendorMattermost Affected 10.11.0 – 10.11.3; 10.5.0 – 10.5.11 Fixed in 11.0.0, 10.11.4, 10.5.12 Patch available CNA
  • github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.11.0 to before 10.11.4 Fixed in 10.11.4 Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.5.0 to before 10.5.12 Fixed in 10.5.12 Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected before 8.0.0-20250905150616-ba86dfc5876b Fixed in 8.0.0-20250905150616-ba86dfc5876b Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost (Go) Vendor— Affected before 5.3.2-0.20250905150616-ba86dfc5876b Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost-server (Go) Vendor— Affected before 5.3.2-0.20250905150616-ba86dfc5876b Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost-server/v5 (Go) Vendor— Affected before 5.3.2-0.20250905150616-ba86dfc5876b Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Patch available GHSA-mqcj-8c2g-h97q
  • github.com/mattermost/mattermost-server/v6 (Go) Vendor— Affected before 5.3.2-0.20250905150616-ba86dfc5876b Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Patch available GHSA-mqcj-8c2g-h97q

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*10.5.0 to before 10.5.12; 10.11.0 to before 10.11.4VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.5.0 to before 10.5.12; 10.11.0 to before 10.11.4 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.0.0, 10.11.4, 10.5.12
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost-server (Go) Fixed in 10.11.4 Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost-server (Go) Fixed in 10.5.12 Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20250905150616-ba86dfc5876b Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost (Go) Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost-server (Go) Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost-server/v5 (Go) Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Advisory →
  • Fix · GHSA-mqcj-8c2g-h97q github.com/mattermost/mattermost-server/v6 (Go) Fixed in 5.3.2-0.20250905150616-ba86dfc5876b Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-11777
  2. 2026-10-03 Alias added: GHSA-mqcj-8c2g-h97q

References

Advisory 2

Other 4

  • 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