CVE-2018-20137 in Fuel
Summary
by MITRE
XSS exists in FUEL CMS 1.4.3 via the Page title, Meta description, or Meta keywords during page data management, as demonstrated by the pages/edit/1?lang=english URI.
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Analysis
by VulDB Data Team • 04/21/2020
The vulnerability CVE-2018-20137 represents a cross-site scripting flaw within FUEL CMS version 1.4.3 that specifically targets the page management functionality. This issue occurs when administrators or authorized users attempt to edit page data through the web interface, particularly affecting the page title, meta description, and meta keywords fields. The vulnerability is exploitable through the pages/edit/1?lang=english URI path, making it accessible to attackers who can manipulate these specific input fields during content management operations.
The technical implementation of this XSS vulnerability stems from insufficient input sanitization and output encoding within the FUEL CMS application. When users enter data into the affected fields, the system fails to properly validate or escape special characters that could be interpreted as executable code by web browsers. This lack of proper sanitization allows malicious payloads to be stored in the database and subsequently executed when the page content is rendered to other users. The vulnerability specifically affects the CMS's content management interface where administrators can modify page metadata, making it a critical concern for sites that rely on user-contributed content or administrative editing capabilities.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with a potential foothold for more sophisticated attacks within the CMS environment. An attacker could inject malicious scripts that redirect users to phishing sites, steal session cookies, or even execute arbitrary commands on the server if additional vulnerabilities exist. The vulnerability is particularly dangerous because it targets administrative functions, potentially allowing attackers to escalate privileges or compromise the entire CMS installation. The fact that this affects the language parameter in the URI suggests that the vulnerability may be exacerbated in multi-language environments where additional input vectors exist.
From a cybersecurity perspective, this vulnerability aligns with CWE-79 which defines Cross-Site Scripting as a common weakness in web applications where user-controllable data is not properly sanitized before being included in web pages. The ATT&CK framework categorizes this as a technique for "Command and Control" and "Persistence" through the use of web-based attacks that can establish malicious web content within legitimate applications. Organizations using FUEL CMS 1.4.3 should immediately implement mitigations including input validation, output encoding, and proper sanitization of all user inputs. The recommended approach includes implementing Content Security Policy headers, validating all input data against whitelists, and ensuring that all user-generated content is properly escaped before rendering in web pages. Additionally, upgrading to a patched version of FUEL CMS or implementing temporary workarounds such as disabling the affected input fields until a proper patch is applied would significantly reduce the risk exposure for affected organizations.