IDOR in CreatePost API allows for timeboxed message disclosure
Priority LOW 29CWE-306Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-306.
Summary
Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of recently created posts.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00371 31st percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 10.9.0, 10.5.8, 10.8.2 +2github.com/mattermost/mattermost-server (Go): 10.5.7, 10.8.2, 10.7.4 +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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mattermost | Mattermost | 10.5.0 – 10.5.6; 10.8.0 – 10.8.1; 10.7.0 – 10.7.3; 9.11.0 – 9.11.16 | 10.9.0, 10.5.8, 10.8.2, 10.7.4, 9.11.17 | Patch available | CNA |
| — | github.com/mattermost/mattermost-server (Go) | 10.5.0 to before 10.5.7 | 10.5.7 | Patch available | GHSA-7h34-9chr-58qh |
| — | github.com/mattermost/mattermost-server (Go) | 10.8.0 to before 10.8.2 | 10.8.2 | Patch available | GHSA-7h34-9chr-58qh |
| — | github.com/mattermost/mattermost-server (Go) | 10.7.0 to before 10.7.4 | 10.7.4 | Patch available | GHSA-7h34-9chr-58qh |
| — | github.com/mattermost/mattermost-server (Go) | 9.11.0 to before 9.11.17 | 9.11.17 | Patch available | GHSA-7h34-9chr-58qh |
| — | github.com/mattermost/mattermost/server/v8 (Go) | before 8.0.0-20250520130510-fa40a8c5d47f | 8.0.0-20250520130510-fa40a8c5d47f | Patch available | GHSA-7h34-9chr-58qh |
- Mattermost VendorMattermost Affected 10.5.0 – 10.5.6; 10.8.0 – 10.8.1; 10.7.0 – 10.7.3; 9.11.0 – 9.11.16 Fixed in 10.9.0, 10.5.8, 10.8.2, 10.7.4, 9.11.17 Patch available CNA
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.5.0 to before 10.5.7 Fixed in 10.5.7 Patch available GHSA-7h34-9chr-58qh
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.8.0 to before 10.8.2 Fixed in 10.8.2 Patch available GHSA-7h34-9chr-58qh
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.7.0 to before 10.7.4 Fixed in 10.7.4 Patch available GHSA-7h34-9chr-58qh
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 9.11.0 to before 9.11.17 Fixed in 9.11.17 Patch available GHSA-7h34-9chr-58qh
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected before 8.0.0-20250520130510-fa40a8c5d47f Fixed in 8.0.0-20250520130510-fa40a8c5d47f Patch available GHSA-7h34-9chr-58qh
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 9.11.0 to before 9.11.17; 10.5.0 to before 10.5.7; 10.7.0 to before 10.7.4; 10.8.0 to before 10.8.2 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 9.11.0 to before 9.11.17; 10.5.0 to before 10.5.7; 10.7.0 to before 10.7.4; 10.8.0 to before 10.8.2 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 10.9.0, 10.5.8, 10.8.2, 10.7.4, 9.11.17
- Fix · GHSA-7h34-9chr-58qh github.com/mattermost/mattermost-server (Go) Fixed in 10.5.7 Advisory →
- Fix · GHSA-7h34-9chr-58qh github.com/mattermost/mattermost-server (Go) Fixed in 10.8.2 Advisory →
- Fix · GHSA-7h34-9chr-58qh github.com/mattermost/mattermost-server (Go) Fixed in 10.7.4 Advisory →
- Fix · GHSA-7h34-9chr-58qh github.com/mattermost/mattermost-server (Go) Fixed in 9.11.17 Advisory →
- Fix · GHSA-7h34-9chr-58qh github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20250520130510-fa40a8c5d47f Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-6226
- 2026-10-03 Alias added: GHSA-7h34-9chr-58qh
References
More Mattermost Server vulnerabilities
- 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
Sources
- CVE-2025-6226 · CVE Program
- CVE-2025-6226 · NVD
- FIRST EPSS
- GHSA-7h34-9chr-58qh · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences