CVE-2019-25445 in Fiverr Clone Script
Summary
by MITRE • 02/20/2026
Fiverr Clone Script 1.2.2 contains a cross-site scripting vulnerability that allows unauthenticated attackers to inject malicious scripts by manipulating the keyword parameter. Attackers can craft URLs with script tags in the keyword parameter of search-results.php to execute arbitrary JavaScript in users' browsers.
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Analysis
by VulDB Data Team • 02/27/2026
The vulnerability identified as CVE-2019-25445 affects the Fiverr Clone Script version 1.2.2, representing a critical cross-site scripting flaw that compromises user browser security. This vulnerability resides within the search functionality of the web application where the keyword parameter in the search-results.php endpoint fails to properly sanitize user input. The flaw allows unauthenticated attackers to inject malicious scripts through crafted URLs that contain script tags within the keyword parameter, creating a persistent threat vector that can be exploited without requiring any authentication credentials or privileged access.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the application's search processing logic. When users navigate to the search results page with maliciously crafted parameters, the application fails to escape or filter special characters that could be interpreted as executable code by web browsers. This weakness directly maps to CWE-79, which categorizes cross-site scripting vulnerabilities as a result of insufficient input validation and output encoding. The vulnerability operates at the application layer where user-supplied data flows directly into web responses without proper sanitization, creating an environment where attacker-controlled content can be executed in the context of other users' browsing sessions.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, and data exfiltration. When legitimate users click on malicious links crafted by attackers, the injected JavaScript code executes in their browsers, potentially stealing cookies, session tokens, or other sensitive information. This threat model aligns with ATT&CK technique T1531 which describes the use of malicious links to execute code in user browsers. The vulnerability affects all users of the affected script regardless of their authentication status, making it particularly dangerous as it can be exploited through social engineering tactics or by simply sharing malicious URLs within the application's user community.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and output encoding mechanisms throughout the application's search functionality. The primary defense involves implementing strict input validation that filters out or escapes potentially dangerous characters including angle brackets, script tags, and other HTML entities before processing user-supplied keywords. Additionally, developers should implement Content Security Policy headers to prevent unauthorized script execution and ensure that all dynamic content is properly escaped when rendered in web responses. The fix should address the root cause by modifying the search-results.php script to sanitize the keyword parameter through proper HTML entity encoding or by implementing a whitelist-based validation approach that only allows safe characters and patterns. Organizations should also consider implementing automated security scanning tools to detect similar vulnerabilities in other parts of their web applications and establish secure coding practices that prevent such issues from recurring in future development cycles.