Incorrect authorization in Mattermost
Priority LOW 29CWE-863Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post actions on posts in that channel via a cookie obtained from any accessible channel.. Mattermost Advisory ID: MMSA-2026-00690
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00299 22nd percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.8.0, 11.7.3, 11.6.5 +1
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 | 11.7.0 – 11.7.2; 11.6.0 – 11.6.4; 10.11.0 – 10.11.19 | 11.8.0, 11.7.3, 11.6.5, 10.11.20 | Patch available | CNA |
- Mattermost VendorMattermost Affected 11.7.0 – 11.7.2; 11.6.0 – 11.6.4; 10.11.0 – 10.11.19 Fixed in 11.8.0, 11.7.3, 11.6.5, 10.11.20 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 10.11.0 to before 10.11.20; 11.6.0 to before 11.6.5; 11.7.0 to before 11.7.3 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.20; 11.6.0 to before 11.6.5; 11.7.0 to before 11.7.3 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 11.8.0, 11.7.3, 11.6.5, 10.11.20
Timeline
- 2026-10-02 Threatist record created from CVE-2026-10106
- 2026-10-03 Alias added: GHSA-vvv9-9jm4-76jg
References
Advisory 1
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-2026-10106 · CVE Program
- CVE-2026-10106 · NVD
- FIRST EPSS
- GHSA-vvv9-9jm4-76jg · 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