CVE-2017-6541 in webpagetest
Summary
by MITRE
Multiple Cross-Site Scripting (XSS) issues were discovered in webpagetest 3.0. The vulnerabilities exist due to insufficient filtration of user-supplied data (benchmark, time) passed to the webpagetest-master/www/benchmarks/viewtest.php URL. An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 02/13/2026
The vulnerability identified as CVE-2017-6541 represents a critical cross-site scripting flaw in webpagetest version 3.0 that exposes the application to persistent and potentially devastating client-side attacks. This issue resides within the webpagetest-master/www/benchmarks/viewtest.php endpoint where the application fails to properly sanitize user-supplied input parameters including benchmark and time data. The absence of adequate input validation and output encoding creates an exploitable condition that allows malicious actors to inject malicious scripts into the application's response. The vulnerability manifests when user-provided data flows directly into the web page without proper sanitization, creating a pathway for attackers to execute arbitrary HTML and JavaScript code within the context of legitimate user sessions.
The technical nature of this vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws arising from insufficient input validation and output encoding. This weakness enables attackers to manipulate the application's behavior by injecting malicious payloads through the benchmark and time parameters that are processed by the vulnerable script. The flaw operates at the application layer where user-supplied data enters the system through HTTP parameters and subsequently flows into the HTML response without proper sanitization. The attack vector is particularly concerning because it allows for persistent XSS attacks where the malicious code can be stored and executed across multiple user sessions, potentially compromising user credentials and browser-based data.
From an operational impact perspective, this vulnerability creates significant security risks for organizations using webpagetest 3.0 for performance monitoring and benchmarking. Attackers can leverage this flaw to hijack user sessions, steal sensitive information, manipulate test results, and potentially gain access to underlying system resources. The vulnerability affects the integrity and confidentiality of test data, as malicious actors can modify benchmark results or inject harmful code that could compromise the entire testing infrastructure. The persistent nature of the flaw means that once exploited, the malicious code can continue to execute against subsequent users who access the affected page, creating a continuous threat vector that extends beyond the initial attack window.
The mitigation strategies for CVE-2017-6541 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application. Organizations should immediately apply the vendor-provided patches or upgrade to a version that addresses this vulnerability. Additionally, implementing proper parameter validation for all user-supplied data, including benchmark and time parameters, will prevent malicious payloads from being processed. The application should employ context-specific output encoding when rendering user data, ensuring that any potentially malicious content is neutralized before being displayed to users. Security measures should include implementing content security policies, using secure coding practices for parameter handling, and conducting regular security assessments to identify similar vulnerabilities in the application's codebase. The remediation process should also involve comprehensive testing to ensure that all input vectors are properly validated and that the application maintains its intended functionality while preventing XSS exploitation.
This vulnerability demonstrates the critical importance of input validation and output encoding in web application security, particularly in performance monitoring tools that handle user-generated data. The flaw represents a common pattern in web application vulnerabilities where insufficient sanitization creates opportunities for attackers to compromise user sessions and manipulate application behavior. Organizations should consider implementing automated security scanning tools to identify similar vulnerabilities across their application portfolio, as this type of issue frequently occurs in web applications that process user input without proper validation mechanisms. The incident highlights the necessity of adhering to secure coding practices and following established security frameworks that address common attack patterns such as those documented in the ATT&CK framework under the web application attack category.