CVE-2021-38346
Published: 14 October 2021
Summary
CVE-2021-38346 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Brizy Brizy-Page Builder. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 11.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-24799
Vulnerability details
The Brizy Page Builder plugin <= 2.3.11 for WordPress allowed authenticated users to upload executable files to a location of their choice using the brizy_create_block_screenshot AJAX action. The file would be named using the id parameter, which could be prepended…
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with "../" to perform directory traversal, and the file contents were populated via the ibsf parameter, which would be base64-decoded and written to the file. While the plugin added a .jpg extension to all uploaded filenames, a double extension attack was still possible, e.g. a file named shell.php would be saved as shell.php.jpg, and would be executable on a number of common configurations.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Validates pathnames and filenames to prevent traversal outside intended directories.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.
Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.
Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.
Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.