Read the docs
TI-2026-63738 Aliases CVE-2026-96260GHSA-p28q-hqh3-qh95

Mattermost server missing request body size limit on plugin routes allows denial of service by an authenticated user

Priority LOW 29CWE-789Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-789.

Summary

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to enforce a request body size limit during CSRF validation of plugin requests which allows an authenticated user to exhaust server memory and cause a denial of service via a large request body sent to a plugin endpoint.. Mattermost Advisory ID: MMSA-2026-00775

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0042 36th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.11.0, 11.9.2, 11.8.6 +2

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
MattermostMattermost11.9.0 – 11.9.1; 11.8.0 – 11.8.5; 11.7.0 – 11.7.10; 11.10.0 – 11.10.111.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2Patch availableCNA
  • Mattermost VendorMattermost Affected 11.9.0 – 11.9.1; 11.8.0 – 11.8.5; 11.7.0 – 11.7.10; 11.10.0 – 11.10.1 Fixed in 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*11.7.0 to before 11.7.11; 11.8.0 to before 11.8.6; 11.9.0 to before 11.9.2; 11.10.0 to before 11.10.2VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 11.7.0 to before 11.7.11; 11.8.0 to before 11.8.6; 11.9.0 to before 11.9.2; 11.10.0 to before 11.10.2 Vulnerable ·Mattermost

Remediation

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-96260
  2. 2026-10-03 Alias added: GHSA-p28q-hqh3-qh95

References

Advisory 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