Unauthorized Read Access to Private Channel Posts via Mattermost Jira Plugin
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 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.
Summary
Mattermost versions 11.1.x <= 11.1.0, 11.0.x <= 11.0.5, 10.12.x <= 10.12.3, 10.11.x <= 10.11.7 fails to validate user channel membership when attaching Mattermost posts as comments to Jira issues, which allows an authenticated attacker with access to the Jira plugin to read post content and attachments from channels they do not have access to.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00194 9th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.2.0, 11.1.1, 11.0.6 +2github.com/mattermost/mattermost/server/v8 (Go): 8.0.0-20251121122154-b57c297c6d7+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 | 11.1.0 – 11.1.0; 11.0.0 – 11.0.5; 10.12.0 – 10.12.3; 10.11.0 – 10.11.7 | 11.2.0, 11.1.1, 11.0.6, 10.12.4, 10.11.8 | Patch available | CNA |
| — | github.com/mattermost/mattermost/server/v8 (Go) | before 8.0.0-20251121122154-b57c297c6d7 | 8.0.0-20251121122154-b57c297c6d7 | Patch available | GHSA-fmqf-pmcm-8cx9 |
| — | github.com/mattermost/mattermost-server (Go) | 10.11.0 to before 10.11.8 | 10.11.8 | Patch available | GHSA-fmqf-pmcm-8cx9 |
| — | github.com/mattermost/mattermost-server (Go) | 10.12.0 to before 10.12.4 | 10.12.4 | Patch available | GHSA-fmqf-pmcm-8cx9 |
| — | github.com/mattermost/mattermost-server (Go) | 11.0.0 to before 11.0.6 | 11.0.6 | Patch available | GHSA-fmqf-pmcm-8cx9 |
| — | github.com/mattermost/mattermost-server (Go) | 11.1.0 to before 11.1.1 | 11.1.1 | Patch available | GHSA-fmqf-pmcm-8cx9 |
- Mattermost VendorMattermost Affected 11.1.0 – 11.1.0; 11.0.0 – 11.0.5; 10.12.0 – 10.12.3; 10.11.0 – 10.11.7 Fixed in 11.2.0, 11.1.1, 11.0.6, 10.12.4, 10.11.8 Patch available CNA
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected before 8.0.0-20251121122154-b57c297c6d7 Fixed in 8.0.0-20251121122154-b57c297c6d7 Patch available GHSA-fmqf-pmcm-8cx9
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.11.0 to before 10.11.8 Fixed in 10.11.8 Patch available GHSA-fmqf-pmcm-8cx9
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 10.12.0 to before 10.12.4 Fixed in 10.12.4 Patch available GHSA-fmqf-pmcm-8cx9
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 11.0.0 to before 11.0.6 Fixed in 11.0.6 Patch available GHSA-fmqf-pmcm-8cx9
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 11.1.0 to before 11.1.1 Fixed in 11.1.1 Patch available GHSA-fmqf-pmcm-8cx9
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 10.11.0 to before 10.11.8; 10.12.0 to before 10.12.4; 11.0.0 to before 11.0.6; 11.1.0 to before 11.1.1 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.8; 10.12.0 to before 10.12.4; 11.0.0 to before 11.0.6; 11.1.0 to before 11.1.1 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 11.2.0, 11.1.1, 11.0.6, 10.12.4, 10.11.8
- Fix · GHSA-fmqf-pmcm-8cx9 github.com/mattermost/mattermost/server/v8 (Go) Fixed in 8.0.0-20251121122154-b57c297c6d7 Advisory →
- Fix · GHSA-fmqf-pmcm-8cx9 github.com/mattermost/mattermost-server (Go) Fixed in 10.11.8 Advisory →
- Fix · GHSA-fmqf-pmcm-8cx9 github.com/mattermost/mattermost-server (Go) Fixed in 10.12.4 Advisory →
- Fix · GHSA-fmqf-pmcm-8cx9 github.com/mattermost/mattermost-server (Go) Fixed in 11.0.6 Advisory →
- Fix · GHSA-fmqf-pmcm-8cx9 github.com/mattermost/mattermost-server (Go) Fixed in 11.1.1 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-13767
- 2026-10-03 Alias added: GHSA-fmqf-pmcm-8cx9
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-2025-13767 · CVE Program
- CVE-2025-13767 · NVD
- FIRST EPSS
- GHSA-fmqf-pmcm-8cx9 · GitHub Advisory Database · CC BY 4.0
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