CVE-2026-93463 in BaserCMS
Summary
by MITRE • 09/30/2026
Cross-Site Scripting via Script Validation Bypass exists in baserCMS. If this vulnerability is exploited, an arbitrary script may be executed in the user's web browser may be caused.
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Analysis
by VulDB Data Team • 09/30/2026
The identified vulnerability represents a classic Cross-Site Scripting (XSS) flaw within the baserCMS content management system, specifically stemming from inadequate validation mechanisms applied to script inputs. This security defect allows an attacker to inject malicious client-side scripts into pages viewed by other users. The core technical failure lies in the application's input sanitization logic, which fails to properly filter or encode special characters that are interpreted as executable code by web browsers. When a user interacts with a compromised entry point, such as a comment field, profile update form, or any area where user-supplied data is reflected back into the HTML output without adequate encoding, the browser interprets the injected payload as legitimate content rather than raw text. This bypass of script validation indicates that the system likely relies on client-side checks or insufficient server-side regex patterns that can be easily circumvented using obfuscation techniques, encoded characters, or alternative event handlers like onload or onerror attributes.
From a technical perspective, this vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The exploitation vector typically involves an attacker crafting a malicious URL or submitting a form containing JavaScript code designed to perform actions on behalf of the victim. Once executed within the context of the trusted baserCMS domain, this script gains access to sensitive cookies, session tokens, and local storage data associated with that domain. This capability effectively allows the attacker to hijack user sessions, steal authentication credentials, or manipulate the visual presentation of the website to deceive users into performing unintended actions such as transferring funds or changing account settings. The impact is severe because it undermines the confidentiality and integrity of the application's user base without requiring direct access to server-side resources.
The operational impact extends beyond simple data theft, potentially leading to defacement of the public-facing interface or the distribution of further malware through drive-by downloads if the injected script loads external malicious payloads. In enterprise environments where baserCMS is used for internal communications or customer portals, this vulnerability can serve as a pivot point for more advanced attacks such as session hijacking and privilege escalation. If an administrator's session is compromised due to their exposure to the vulnerable page, the attacker may gain administrative control over the CMS, allowing them to install backdoors, modify site configurations, or exfiltrate database contents containing sensitive user information. This scenario highlights the critical importance of securing input validation layers in web applications that handle dynamic content generation.
To mitigate this vulnerability, developers must implement strict output encoding for all data rendered in HTML contexts, ensuring that special characters are converted to their corresponding HTML entities before being displayed. Input validation should be enforced on both the client and server sides, utilizing allowlists rather than blocklists to define acceptable input formats. Additionally, deploying Content Security Policy headers can significantly reduce the risk of successful exploitation by restricting the sources from which scripts can be loaded or executed. Regular security audits and static code analysis tools focused on detecting XSS patterns are essential for maintaining long-term resilience against such injection attacks within the baserCMS ecosystem.