CVE-2026-25581 is a cross-site scripting (XSS) vulnerability identified in samclarke's SCEditor, a lightweight WYSIWYG BBCode and XHTML editor widely used in web applications for rich text editing. The vulnerability exists in versions prior to 3.2.1 and stems from improper neutralization of input during web page generation (CWE-79). Specifically, if an attacker can influence configuration options passed to the sceditor.create() function—such as emoticons, charset, or other customizable parameters—these inputs are not adequately sanitized before being rendered. This lack of sanitization allows an attacker to inject malicious scripts into the editor's output, which can then execute in the context of the victim's browser. Exploitation requires the attacker to have the ability to control configuration options, which typically implies some level of privilege or access to the application’s configuration interface. Additionally, user interaction is necessary to trigger the malicious script execution. The vulnerability impacts confidentiality and integrity by potentially allowing theft of session tokens, user credentials, or manipulation of displayed content. Availability is not affected. The vulnerability has a CVSS v3.1 base score of 5.4 (medium severity), with attack vector network, low attack complexity, requiring privileges, and user interaction. The scope is changed, indicating that the vulnerability affects components beyond the initially vulnerable module. No known exploits have been reported in the wild as of the publication date. The issue is resolved in SCEditor version 3.2.1, which includes proper sanitization of configuration inputs to prevent script injection.

For European organizations, this vulnerability poses a moderate risk primarily to web applications that integrate SCEditor versions prior to 3.2.1. Successful exploitation could lead to unauthorized disclosure of sensitive information such as session cookies or personal data, violating GDPR requirements and potentially resulting in regulatory penalties. Integrity of displayed content could be compromised, undermining user trust and damaging organizational reputation. Since exploitation requires some level of privilege to control configuration options, insider threats or compromised accounts could leverage this vulnerability to escalate attacks. The necessity of user interaction means phishing or social engineering could be used to trigger the payload. While availability is unaffected, the confidentiality and integrity impacts are significant enough to warrant prompt remediation. Organizations in sectors with high regulatory scrutiny, such as finance, healthcare, and government, are particularly at risk. Additionally, web portals or collaborative platforms using SCEditor for content editing are potential targets for attackers aiming to inject malicious scripts to harvest credentials or perform session hijacking.

1. Upgrade all instances of SCEditor to version 3.2.1 or later, which includes the necessary sanitization fixes. 2. Restrict access to configuration options passed to sceditor.create() to trusted administrators only, preventing unprivileged users from modifying these parameters. 3. Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 4. Conduct thorough input validation and sanitization on all user-controllable inputs at the application level, not relying solely on the editor’s internal mechanisms. 5. Monitor web application logs for unusual configuration changes or script injection attempts. 6. Educate users about phishing and social engineering risks that could trigger malicious payloads requiring user interaction. 7. Perform regular security assessments and penetration testing focused on web application components integrating SCEditor to detect any residual or related vulnerabilities.