CVE-2021-47751 in CuteEditor
Summary
by MITRE • 01/14/2026
CuteEditor for PHP (now referred to as Rich Text Editor) 6.6 contains a directory traversal vulnerability in the browse template feature that allows attackers to write files to arbitrary web root directories. Attackers can exploit the ServerMapPath() function by renaming uploaded HTML files using directory traversal sequences to write files outside the intended template directory.
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Analysis
by VulDB Data Team • 02/02/2026
The vulnerability CVE-2021-47751 affects CuteEditor for PHP version 6.6, which is now known as Rich Text Editor, and represents a critical directory traversal flaw within the browse template functionality. This issue stems from insufficient input validation and improper path handling within the ServerMapPath() function, creating a significant security risk for web applications that utilize this component. The flaw allows remote attackers to manipulate file upload operations by exploiting the way the application processes directory traversal sequences during HTML file renaming processes.
The technical implementation of this vulnerability occurs when the ServerMapPath() function fails to properly sanitize user-supplied input during file upload operations. Attackers can craft malicious filenames containing directory traversal sequences such as ../ or ..\ that bypass intended security restrictions. When the application processes these manipulated filenames, it incorrectly resolves the paths, allowing file writing operations to occur outside the designated template directory boundaries. This misconfiguration creates a path traversal condition that can be exploited to write arbitrary files to any location within the web server's accessible directory structure.
The operational impact of this vulnerability extends beyond simple unauthorized file writing capabilities. Attackers can leverage this flaw to upload malicious files such as web shells, backdoors, or other payloads that can compromise the entire web application and underlying server infrastructure. The vulnerability enables attackers to potentially execute arbitrary code with the privileges of the web server process, creating a persistent threat vector that can be used for data exfiltration, system compromise, or as a foothold for further network penetration. The attack surface is particularly concerning because it allows exploitation of the web root directory, potentially enabling complete server takeover.
This vulnerability aligns with CWE-22 Directory Traversal and CWE-73 Path Traversal, both of which are categorized under the Common Weakness Enumeration framework and represent fundamental security flaws in path handling mechanisms. From an adversarial perspective, this vulnerability maps directly to ATT&CK technique T1059 Command and Scripting Interpreter, as attackers can use the uploaded malicious files to execute commands on the compromised system. The vulnerability also relates to T1505 Server Software Component, as it exploits a flaw in third-party web editing software. Organizations should implement immediate mitigations including input validation, path sanitization, and restricting file upload capabilities to prevent exploitation. Additionally, web application firewalls should be configured to detect and block directory traversal attempts, while regular security audits should be conducted to identify similar vulnerabilities in other third-party components.