An issue was discovered in Mattermost Server before 5.2, 5.1.1, 5.0.3, and 4.10.3.
Priority LOW 21CWE-732Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
An issue was discovered in Mattermost Server before 5.2, 5.1.1, 5.0.3, and 4.10.3. Attackers could use multiple e-mail addresses to bypass a domain-based policy for signups.
Why it matters now
EPSS 0.00615 49th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | before 4.10.3; 5.0.0 to before 5.0.3; 5.1.0 to before 5.1.1 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc1:*:*:*:*:*:* | 5.2.0 rc1 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc2:*:*:*:*:*:* | 5.2.0 rc2 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc3:*:*:*:*:*:* | 5.2.0 rc3 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc4:*:*:*:*:*:* | 5.2.0 rc4 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc5:*:*:*:*:*:* | 5.2.0 rc5 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc6:*:*:*:*:*:* | 5.2.0 rc6 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions before 4.10.3; 5.0.0 to before 5.0.3; 5.1.0 to before 5.1.1 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc1:*:*:*:*:*:* Versions 5.2.0 rc1 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc2:*:*:*:*:*:* Versions 5.2.0 rc2 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc3:*:*:*:*:*:* Versions 5.2.0 rc3 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc4:*:*:*:*:*:* Versions 5.2.0 rc4 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc5:*:*:*:*:*:* Versions 5.2.0 rc5 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:5.2.0:rc6:*:*:*:*:*:* Versions 5.2.0 rc6 Vulnerable ·Mattermost
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2018-21252
- 2026-10-03 Alias added: GHSA-v2fx-xxc9-4xq2
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-2018-21252 · CVE Program
- CVE-2018-21252 · NVD
- FIRST EPSS
- GHSA-v2fx-xxc9-4xq2 · GitHub Advisory Database · CC BY 4.0
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