CVE-2025-7821 is a security vulnerability identified in the WC Plus plugin for WordPress, affecting all versions up to and including 1.2.0. The vulnerability arises from a missing authorization check on the AJAX action 'pluswc_logo_favicon_logo_base'. Specifically, this means that the plugin does not verify whether the requester has the necessary permissions before allowing modification of the site's favicon logo base. Because this AJAX endpoint is accessible without authentication, an unauthenticated attacker can exploit this flaw to update the favicon logo base arbitrarily. While this does not directly impact the confidentiality or availability of the site, it compromises the integrity of the website's appearance and branding. The vulnerability is classified under CWE-862 (Missing Authorization), indicating that the system fails to enforce proper access control. The CVSS v3.1 base score is 5.3 (medium severity), reflecting the ease of exploitation (no authentication or user interaction required) but limited impact confined to integrity of a non-critical asset. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability is significant because unauthorized modification of site assets can be leveraged in broader attack campaigns, such as phishing or defacement, potentially undermining user trust and brand reputation.

For European organizations using the WC Plus WordPress plugin, this vulnerability poses a risk primarily to website integrity and brand trust. Although it does not allow direct data theft or site takeover, unauthorized favicon changes can be used to mislead visitors, potentially facilitating phishing attacks or social engineering by presenting malicious content under the guise of a legitimate site. This can lead to reputational damage, loss of customer confidence, and potential regulatory scrutiny under GDPR if user trust is compromised. Organizations in sectors with high public visibility such as e-commerce, media, and government websites are particularly vulnerable. Additionally, repeated or widespread exploitation could result in increased operational costs due to incident response and remediation efforts. Since the vulnerability requires no authentication and no user interaction, attackers can automate exploitation at scale, increasing the risk of mass defacements or brand abuse across multiple affected sites.

To mitigate this vulnerability, European organizations should immediately audit their WordPress installations for the presence of the WC Plus plugin and verify the version in use. Until an official patch is released, organizations should consider disabling the plugin or restricting access to the affected AJAX endpoint via web application firewall (WAF) rules or server-level access controls to block unauthenticated requests to 'pluswc_logo_favicon_logo_base'. Implementing strict Content Security Policy (CSP) headers can help limit the impact of unauthorized favicon changes by controlling which resources browsers load. Monitoring website integrity through automated tools that detect unauthorized changes to site assets, including favicons, is recommended to enable rapid detection and response. Organizations should also maintain regular backups of website assets to facilitate quick restoration if defacement occurs. Finally, once a patch is available, prompt application of the update is critical to fully remediate the vulnerability.