CVE-2019-9553 in Bolt
Summary
by MITRE
Bolt 3.6.4 has XSS via the slug, teaser, or title parameter to editcontent/pages, a related issue to CVE-2017-11128 and CVE-2018-19933.
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Analysis
by VulDB Data Team • 08/09/2025
Bolt CMS version 3.6.4 contains a cross-site scripting vulnerability that affects the editcontent and pages functionality through manipulation of the slug, teaser, or title parameters. This vulnerability represents a regression in the security posture of the platform, as it builds upon previously identified issues such as CVE-2017-11128 and CVE-2018-19933, indicating a persistent failure in proper input sanitization and output encoding mechanisms within the content management system. The flaw allows attackers to inject malicious scripts into these specific content parameters, which are then executed in the context of other users' browsers when they view the affected content.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input values before they are rendered in the web interface. When administrators or users interact with the editcontent or pages endpoints, the system fails to properly encode or escape special characters in the slug, teaser, or title fields, creating an opening for malicious script execution. This occurs because the application does not implement proper context-aware output encoding, a fundamental security principle that ensures that data inserted into different contexts such as HTML attributes, JavaScript contexts, or CSS contexts is appropriately escaped. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates a failure in input validation and output encoding practices that are essential for preventing injection attacks.
The operational impact of this vulnerability is significant as it allows for arbitrary code execution in the browsers of unsuspecting users who access the affected content. Attackers could potentially steal session cookies, perform unauthorized actions on behalf of users, redirect victims to malicious sites, or even deliver malware through the exploited XSS vector. The vulnerability affects the core content management functionality of Bolt CMS, making it particularly dangerous as it could be exploited by attackers with minimal privileges to compromise the entire content management system. The attack surface is broadened because these parameters are commonly used in content creation and editing workflows, making the exploitation relatively straightforward for threat actors who understand the application's structure.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding measures across all user-supplied parameters. Organizations should immediately upgrade to a patched version of Bolt CMS that addresses this specific XSS vulnerability, as the vendor likely released security updates to resolve the encoding issues in the affected parameters. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against script execution, while regular security audits of input handling mechanisms should be conducted to identify similar vulnerabilities. The remediation approach should align with ATT&CK technique T1203, which covers exploitation of web application vulnerabilities, and organizations should ensure their security monitoring systems can detect and alert on suspicious parameter manipulation patterns that might indicate exploitation attempts.