CVE-2026-88415 in MCMS
Summary
by MITRE • 09/22/2026
MCMS 6.1.1 through 6.2.1 is vulnerable to stored Cross-Site Scripting (XSS). The article content field `contentDetails` is excluded from the global XSS filter.
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Analysis
by VulDB Data Team • 09/22/2026
The vulnerability identified in MCMS versions 6.1.1 through 6.2.1 represents a classic instance of Stored Cross-Site Scripting, technically classified under CWE-79: Improper Neutralization of Input During Web Page Generation. This flaw arises from an insufficient input validation and sanitization mechanism within the application's content management subsystem. Specifically, the field designated as `contentDetails`, which is intended to store article body text or rich media descriptions, was inadvertently excluded from the global XSS filtering routine that processes other user inputs across the platform. By bypassing this centralized security control, the application fails to strip or encode potentially malicious script payloads before persisting them in the backend database. This architectural oversight creates a persistent attack vector where injected code is not merely executed during immediate input processing but remains stored on the server for subsequent retrieval and rendering by other users.
From an operational perspective, this vulnerability allows attackers with write access to article content fields to inject client-side scripts that execute within the context of any user viewing the affected articles. The impact extends beyond simple defacement or local session hijacking; because the payload is stored, it affects every victim who accesses the compromised page without requiring further interaction from the attacker after the initial injection. This persistence significantly amplifies the severity of the issue, as a single successful exploit can compromise multiple user accounts over time. Attackers may leverage this capability to steal sensitive information such as session cookies, authentication tokens, or personally identifiable data displayed on the page. Furthermore, if the application supports administrative features accessible through these views, attackers could potentially escalate privileges by manipulating admin interfaces via scripted DOM manipulation, leading to a complete compromise of the content management system and its underlying infrastructure.
The technical root cause lies in the inconsistent implementation of security controls across different input fields within the MCMS framework. While most fields benefit from a global filter that neutralizes special characters like angle brackets, quotes, and script tags, the `contentDetails` field operates outside this protective boundary. This inconsistency suggests either an oversight during development or a deliberate exclusion for functionality reasons that was not adequately secured with alternative measures such as context-aware encoding at render time. In modern web application security frameworks, defense in depth requires that even if input validation fails to catch malicious data, output encoding must ensure that the browser interprets the content strictly as text rather than executable code. The absence of this secondary layer for the `contentDetails` field leaves the application vulnerable regardless of any upstream filtering attempts.
To mitigate this vulnerability and prevent future occurrences, immediate remediation should focus on enforcing strict input validation and robust output encoding for all user-controllable fields within MCMS. Developers must ensure that the global XSS filter is applied uniformly to every data entry point, including `contentDetails`, or alternatively implement context-specific HTML entity encoding when rendering content in web pages. This ensures that any special characters are converted into their safe textual equivalents before being sent to the client browser. Additionally, implementing a Content Security Policy (CSP) header can provide an effective layer of defense by restricting the sources from which scripts can be loaded and executed, thereby mitigating the impact even if some malicious content slips through validation filters. Regular security audits and static code analysis should also be employed to identify similar inconsistencies in input handling across other modules within the application suite.
In terms of industry-standard mapping, this vulnerability aligns with MITRE ATT&CK technique T1059: Command and Scripting Interpreter, specifically when used for client-side script execution via web browsers (T1059.007). It also relates to CWE-834: Excessive Iterative Restriction, indicating a failure in the iterative process of sanitizing inputs against known attack patterns. Organizations managing MCMS deployments should prioritize patching these versions or applying the recommended configuration changes immediately to close this persistent security gap and protect user data integrity.