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 root cause is the absence of nonce validation on the settings update endpoint, which is responsible for updating the plugin's Calendly API key. Nonces in WordPress are security tokens used to verify that requests are intentional and originate from legitimate users. Without nonce validation, attackers can craft malicious requests that, when executed by an authenticated administrator (via clicking a link or visiting a crafted webpage), cause unauthorized changes to the plugin's configuration. This can lead to integrity compromise by allowing attackers to replace the legitimate API key with one under their control, potentially redirecting scheduling data or manipulating booking workflows. The vulnerability does not require authentication from the attacker but does require user interaction by an administrator, limiting ease of exploitation. The CVSS v3.1 score is 4.3, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no confidentiality impact (C:N), low integrity impact (I:L), and no availability impact (A:N). No patches or exploits are currently documented, but the risk remains for sites that have not updated or mitigated this issue. The vulnerability was published on December 12, 2025, and assigned by Wordfence.

For European organizations, this vulnerability poses a moderate risk primarily to the integrity of their WordPress sites using the Upcoming for Calendly plugin. Unauthorized modification of the Calendly API key could allow attackers to hijack scheduling functionalities, potentially redirecting appointments or injecting malicious data into booking workflows. This could disrupt business operations, cause reputational damage, or lead to indirect data exposure if attackers manipulate scheduling communications. Since the exploit requires an administrator to interact with a malicious link, social engineering campaigns targeting site admins could be effective. Organizations relying heavily on online scheduling and customer interaction through WordPress sites are at higher risk. The impact on confidentiality and availability is minimal, but integrity compromise can have downstream effects on trust and operational continuity. Given the widespread use of WordPress across Europe and the popularity of scheduling tools, the threat is relevant to many sectors including SMEs, service providers, and public institutions.

To mitigate CVE-2025-14160, organizations should immediately update the Upcoming for Calendly plugin to a patched version once available. In the absence of a patch, administrators should implement manual nonce validation on the settings update endpoint by modifying the plugin code to verify WordPress nonces before processing requests. Additionally, administrators should be trained to recognize and avoid clicking suspicious links, especially those that could trigger administrative actions. Employing Web Application Firewalls (WAFs) with custom rules to detect and block unauthorized POST requests to the plugin’s settings endpoint can provide temporary protection. Limiting administrative access to trusted networks and enforcing multi-factor authentication (MFA) for WordPress admin accounts reduces the risk of successful social engineering. Regular monitoring of plugin settings and API keys for unauthorized changes is also recommended. Finally, organizations should maintain an inventory of WordPress plugins and their versions to quickly identify vulnerable instances.