CVE-2025-14160 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Upcoming for Calendly plugin for WordPress, affecting all versions up to and including 1.2.4. The vulnerability stems from the absence of nonce validation on the plugin's settings update functionality, which is a security mechanism designed to ensure that requests modifying settings originate from legitimate users and not from forged external sources. Due to this missing validation, an unauthenticated attacker can craft a malicious request that, if an administrator clicks on a specially crafted link or visits a malicious webpage, causes the plugin's Calendly API key to be updated without the administrator's consent. This attack vector does not require the attacker to be authenticated on the WordPress site, but it does require user interaction from an administrator, making it a UI:R (User Interaction Required) vulnerability. The impact primarily affects the integrity of the plugin's configuration, potentially allowing attackers to redirect or disrupt Calendly scheduling integrations by substituting the API key. The CVSS 3.1 base score is 4.3, reflecting a medium severity level due to the limited impact on confidentiality and availability, and the requirement for user interaction. No known exploits have been reported in the wild, and no patches are currently linked, indicating that mitigation may require manual intervention or awaiting an official update. The vulnerability is cataloged under CWE-352, a common web security weakness related to CSRF attacks.

For European organizations, this vulnerability poses a risk primarily to the integrity of scheduling and calendar integrations that rely on the Upcoming for Calendly plugin. Unauthorized modification of the Calendly API key could lead to disruption of automated scheduling workflows, potential data misrouting, or denial of service for appointment booking functionalities. Organizations that depend heavily on Calendly for customer or internal scheduling may experience operational inefficiencies or reputational damage if scheduling is compromised. While the vulnerability does not directly expose sensitive data or cause system downtime, the manipulation of API keys could be leveraged as a foothold for further attacks or social engineering. The requirement for administrator interaction reduces the likelihood of widespread exploitation but does not eliminate risk, especially in environments with less stringent user security awareness or where phishing attacks are prevalent. Given the widespread use of WordPress in Europe and the popularity of scheduling tools, this vulnerability could affect a significant number of organizations, particularly SMEs and service providers integrating Calendly into their websites.

European organizations should immediately audit their WordPress installations to identify the presence of the Upcoming for Calendly plugin and verify the version in use. Until an official patch is released, administrators should implement manual nonce validation on the plugin's settings update endpoints to prevent unauthorized requests. Restricting administrative access to trusted networks and enforcing multi-factor authentication (MFA) for WordPress admin accounts can reduce the risk of successful exploitation. User training focused on recognizing phishing attempts and avoiding clicking on suspicious links is critical to mitigate the user interaction requirement. Monitoring web server logs for unusual POST requests to the plugin's settings endpoints can help detect attempted exploitation. Organizations should subscribe to vendor advisories and apply updates promptly once patches become available. Additionally, consider temporarily disabling or removing the plugin if it is not essential, or replacing it with alternative scheduling integrations that follow secure development practices.