CVE-2026-7016 in MaxSite
Summary
by MITRE • 04/26/2026
A vulnerability was found in MaxSite CMS up to 109.3. Impacted is an unknown function of the component ushki Plugin. Performing a manipulation of the argument f_ushka_new/f_ushk results in cross site scripting. Remote exploitation of the attack is possible. The exploit has been made public and could be used. Upgrading to version 109.4 is recommended to address this issue. The patch is named 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7. Upgrading the affected component is recommended. The vendor was informed early about this issue. They classify it as a "Self-XSS". They deployed a countermeasure: "Nevertheless, we consider this a violation of secure coding standards. The lack of filtering via `htmlspecialchars()` has already been fixed in the latest patch to prevent incorrect data display."
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Analysis
by VulDB Data Team • 06/26/2026
This vulnerability exists within the MaxSite CMS platform specifically affecting version 109.3 and earlier, where an insecure input handling flaw has been identified in the ushki Plugin component. The issue manifests through manipulation of the f_ushka_new/f_ushk arguments which creates a cross-site scripting condition that can be exploited remotely. The vulnerability represents a classic self-xss scenario as classified by the vendor, though it's important to note that even self-xss attacks can pose significant security risks when they involve data persistence or can be leveraged in combination with other attack vectors.
The technical implementation flaw stems from insufficient input validation and output sanitization within the plugin's argument handling mechanism. When user-supplied data is processed through these parameters without proper escaping or filtering, malicious scripts can be injected into the application's response stream. This allows attackers to execute arbitrary javascript code within the context of other users' browsers, potentially leading to session hijacking, credential theft, or further exploitation of the compromised sessions.
The operational impact of this vulnerability extends beyond simple script execution as it represents a failure in secure coding practices that violates fundamental security principles outlined in CWE-79 - Improper Neutralization of Input During Web Page Generation. The vendor's acknowledgment of the issue through their patch 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7 demonstrates recognition of the security gap that exists in their codebase. While they categorize it as self-xss, this classification does not diminish the importance of addressing the underlying vulnerability which could be exploited in more sophisticated attack scenarios.
Security practitioners should consider this vulnerability in the context of broader attack patterns documented in the MITRE ATT&CK framework under techniques related to client-side exploitation and credential access. The fact that a public exploit exists increases the risk profile significantly, as it removes the requirement for advanced technical skills to leverage the vulnerability. Organizations running affected versions of MaxSite CMS should prioritize immediate patching to prevent potential compromise of user sessions and data integrity.
The vendor's response includes implementation of htmlspecialchars() filtering as a countermeasure against incorrect data display, which aligns with recommended practices for preventing xss vulnerabilities in web applications. This approach addresses the immediate security concern by ensuring that any special characters in user input are properly escaped during output rendering, thereby preventing malicious scripts from executing in browser contexts. However, the fundamental principle of input validation and sanitization remains critical for maintaining robust security posture across all application components.
The remediation strategy should focus on upgrading to version 109.4 or later where the patch has been applied, as specified by the vendor's advisory. System administrators must ensure that all instances of the ushki plugin are updated and that proper testing is performed to verify that the patch does not introduce any compatibility issues with existing functionality. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any other potential input handling vulnerabilities within their MaxSite CMS installations or related plugins that may present similar security risks.