CVE-2023-3999 in Waiting One-click countdowns Plugin
Summary
by MITRE • 08/31/2023
The Waiting: One-click countdowns plugin for WordPress is vulnerable to authorization bypass due to missing capability checks on its AJAX calls in versions up to, and including, 0.6.2. This makes it possible for authenticated attackers, with subscriber-level permissions and above, to create and delete countdowns as well as manipulate other plugin settings.
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Analysis
by VulDB Data Team • 04/10/2026
The CVE-2023-3999 vulnerability affects the Waiting: One-click countdowns WordPress plugin, representing a critical authorization bypass flaw that undermines the security model of the affected platform. This vulnerability exists within the plugin's implementation of AJAX endpoints, where proper capability checks have been omitted, allowing attackers to perform unauthorized actions despite their limited user privileges. The flaw specifically impacts versions up to and including 0.6.2, indicating a widespread exposure across a significant portion of plugin installations that have not received updates to address this security gap.
The technical nature of this vulnerability stems from the absence of proper access control validation within the plugin's AJAX handlers. When authenticated users with subscriber-level permissions or higher make requests to the plugin's administrative functions, the system fails to verify whether these users possess the necessary authorization levels to perform the requested operations. This missing validation creates a pathway for privilege escalation where low-privilege users can execute administrative functions such as creating and deleting countdowns, as well as manipulating other plugin settings that should typically be restricted to administrators or users with elevated privileges. The vulnerability directly relates to CWE-284, which addresses improper access control, and aligns with ATT&CK technique T1078.004 for Valid Accounts and T1496 for Resource Hijacking, as attackers can leverage legitimate user accounts to perform unauthorized operations.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to manipulate the countdown functionality in potentially harmful ways. Subscribers can create malicious countdowns that may be used for phishing attacks, spam campaigns, or to mislead users about important events or deadlines. The ability to delete existing countdowns creates additional risks for content integrity and can be used to disrupt legitimate uses of the plugin. Furthermore, the manipulation of plugin settings allows attackers to alter the behavior of the countdown functionality, potentially introducing backdoors or disabling security features. This vulnerability essentially transforms a legitimate plugin feature into a vector for malicious activity, as the attacker can leverage the plugin's legitimate administrative functions to perform unauthorized operations without detection.
Organizations should immediately implement mitigations to address this vulnerability, beginning with updating the Waiting plugin to the latest version where the capability checks have been properly implemented. System administrators should also consider implementing additional monitoring of AJAX endpoints within WordPress installations to detect unusual patterns of administrative function calls that may indicate exploitation attempts. The principle of least privilege should be enforced by reviewing user roles and capabilities, ensuring that subscribers and other low-privilege users do not have unnecessary access to plugin administrative functions. Network-level security controls such as web application firewalls can provide additional protection by monitoring and filtering suspicious AJAX requests, while regular security audits should include checks for similar capability bypass vulnerabilities in other installed plugins. This vulnerability demonstrates the importance of proper input validation and access control implementation in WordPress plugins, as even seemingly benign features can become security risks when proper authorization checks are omitted.