Admin RCE via Malicious Plugin Upload on CI Test Instances
Priority LOW 31CWE-863Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00348 28th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.4.0, 11.3.1, 11.2.3 +1
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
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 | 11.3.0 – 11.3.0; 11.2.0 – 11.2.2; 10.11.0 – 10.11.10 | 11.4.0, 11.3.1, 11.2.3, 10.11.11 | Patch available | CNA |
- Mattermost VendorMattermost Affected 11.3.0 – 11.3.0; 11.2.0 – 11.2.2; 10.11.0 – 10.11.10 Fixed in 11.4.0, 11.3.1, 11.2.3, 10.11.11 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 10.11.0 to before 10.11.11; 11.2.0 to before 11.2.3; 11.3.0 to before 11.3.1 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 10.11.0 to before 10.11.11; 11.2.0 to before 11.2.3; 11.3.0 to before 11.3.1 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 11.4.0, 11.3.1, 11.2.3, 10.11.11
Timeline
- 2026-10-02 Threatist record created from CVE-2026-2462
- 2026-10-03 Alias added: GHSA-fprx-ppqr-8wgf
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-2026-2462 · CVE Program
- CVE-2026-2462 · NVD
- FIRST EPSS
- GHSA-fprx-ppqr-8wgf · GitHub Advisory Database · CC BY 4.0
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