MJML allows mj-include directory traversal due to an incomplete fix for CVE-2020-12827
Date: 2025-12
Affected: npm/mjml
Attack vector: path-traversal
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2020-12827
CVE-2025-67898
CWE: CWE-22
CWE-36
CVSS: 4.5 (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:L)

MJML before 5.0.0-alpha.9 allows mj-include directory traversal to test file existence and (in the type="css" case) read files. NOTE: this issue exists because of an incomplete fix for CVE-2020-12827.


Mitigations:

Architectural layers (MAESTRO):