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TI-2025-34763 Aliases CVE-2025-55073GHSA-ff85-qw3h-g9vp

MS Teams plugin OAuth allows editing arbitrary posts

Priority LOW 24CWE-306Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-306.

Summary

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to validate the relationship between the post being updated and the MSTeams plugin OAuth flow which allows an attacker to edit arbitrary posts via a crafted MSTeams plugin OAuth redirect URL.

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, 10.5.12 +1github.com/mattermost/mattermost-server (Go): 10.11.4, 10.5.12, 10.12.1+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
MattermostMattermost10.11.0 – 10.11.3; 10.5.0 – 10.5.11; 10.12.0 – 10.12.011.0.0, 10.11.4, 10.5.12, 10.12.1Patch availableCNA
—github.com/mattermost/mattermost-server (Go)10.11.0 to before 10.11.410.11.4Patch availableGHSA-ff85-qw3h-g9vp
—github.com/mattermost/mattermost-server (Go)10.5.0 to before 10.5.1210.5.12Patch availableGHSA-ff85-qw3h-g9vp
—github.com/mattermost/mattermost-server (Go)10.12.0 to before 10.12.110.12.1Patch availableGHSA-ff85-qw3h-g9vp
—github.com/mattermost/mattermost/server/v8 (Go)before 8.0.0-20250929212932-a41db04d27468.0.0-20250929212932-a41db04d2746Patch availableGHSA-ff85-qw3h-g9vp
  • Mattermost VendorMattermost Affected 10.11.0 – 10.11.3; 10.5.0 – 10.5.11; 10.12.0 – 10.12.0 Fixed in 11.0.0, 10.11.4, 10.5.12, 10.12.1 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-ff85-qw3h-g9vp
  • github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.5.0 to before 10.5.12 Fixed in 10.5.12 Patch available GHSA-ff85-qw3h-g9vp
  • github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.12.0 to before 10.12.1 Fixed in 10.12.1 Patch available GHSA-ff85-qw3h-g9vp
  • github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected before 8.0.0-20250929212932-a41db04d2746 Fixed in 8.0.0-20250929212932-a41db04d2746 Patch available GHSA-ff85-qw3h-g9vp

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 10.11.4; 10.12.0 to before 10.12.1VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.5.0 to before 10.5.12; 10.11.0 to before 10.11.4; 10.12.0 to before 10.12.1 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.0.0, 10.11.4, 10.5.12, 10.12.1
  • Fix · GHSA-ff85-qw3h-g9vp github.com/mattermost/mattermost-server (Go) Fixed in 10.11.4 Advisory →
  • Fix · GHSA-ff85-qw3h-g9vp github.com/mattermost/mattermost-server (Go) Fixed in 10.5.12 Advisory →
  • Fix · GHSA-ff85-qw3h-g9vp github.com/mattermost/mattermost-server (Go) Fixed in 10.12.1 Advisory →
  • Fix · GHSA-ff85-qw3h-g9vp github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20250929212932-a41db04d2746 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-55073
  2. 2026-10-03 Alias added: GHSA-ff85-qw3h-g9vp

References

Advisory 2

Other 6

  • 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