CVE-2025-9879 is a stored Cross-Site Scripting (XSS) vulnerability affecting the Spotify Embed Creator plugin for WordPress, developed by slowmove. This vulnerability exists in all versions up to and including 1.0.5. The root cause is improper neutralization of input during web page generation (CWE-79), specifically due to insufficient sanitization and output escaping of user-supplied attributes in the plugin's 'spotify' shortcode. An authenticated attacker with contributor-level access or higher can exploit this flaw by injecting arbitrary JavaScript code into pages or posts using the vulnerable shortcode. When any user, including administrators or site visitors, accesses the compromised page, the malicious script executes in their browser context. This can lead to session hijacking, privilege escalation, defacement, or redirection to malicious sites. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector of network, low attack complexity, requiring privileges (contributor or above), no user interaction, and a scope change. The impact affects confidentiality and integrity but not availability. No known exploits are reported in the wild as of the publication date (September 12, 2025). No official patches or updates have been linked yet, so mitigation relies on access control and input validation best practices. The vulnerability is particularly relevant for WordPress sites that use this plugin to embed Spotify content, which is common among music blogs, entertainment sites, and media outlets.

For European organizations, this vulnerability poses a moderate risk, especially for those running WordPress sites with the Spotify Embed Creator plugin installed. Exploitation could allow attackers to execute malicious scripts in the context of the affected website, potentially leading to theft of user credentials, session tokens, or other sensitive information. This can undermine user trust and lead to reputational damage. In regulated sectors such as finance, healthcare, or public services, such breaches could also result in non-compliance with GDPR due to inadequate protection of personal data. The scope of impact includes website administrators, contributors, and end-users interacting with compromised pages. Since the vulnerability requires contributor-level access, insider threats or compromised contributor accounts increase risk. Attackers could leverage this vulnerability to pivot further into organizational networks if administrative users are targeted. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits in the future. Organizations relying on WordPress for public-facing content should consider this vulnerability in their risk assessments and incident response planning.

1. Restrict contributor-level access strictly to trusted users and regularly audit user roles and permissions to minimize the risk of insider exploitation. 2. Implement Web Application Firewalls (WAFs) with rules to detect and block malicious payloads targeting the 'spotify' shortcode or suspicious script injections. 3. Apply strict Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. 4. Monitor site content for unexpected script tags or unusual shortcode usage patterns that may indicate exploitation attempts. 5. Until an official patch is released, consider disabling or removing the Spotify Embed Creator plugin if it is not essential. 6. Educate content contributors about secure content practices and the risks of injecting untrusted code. 7. Keep WordPress core and all plugins updated to the latest versions once patches addressing this vulnerability become available. 8. Employ security plugins that can detect and sanitize XSS payloads in user-generated content. 9. Regularly back up website data to enable quick restoration in case of compromise.