CVE-2026-92427 in Coinsnap Bitcoin Crowdfunding Plugin
Summary
by MITRE • 10/16/2026
The Coinsnap Bitcoin Crowdfunding WordPress plugin through 1.2.0 does not restrict access to the secret used to authenticate its payment gateway webhook, disclosing it to unauthenticated users and rendering the webhook's signature check ineffective. This allows unauthenticated attackers to forge payment-confirmation notifications and record arbitrary donations as completed, with attacker-chosen amounts, donor names and messages.
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Analysis
by VulDB Data Team • 10/16/2026
The Coinsnap Bitcoin Crowdfunding WordPress plugin version 1.2.0 contains a critical authentication bypass vulnerability that fundamentally compromises the integrity of its cryptocurrency donation processing system. This flaw stems from an improper access control mechanism where the secret key required to validate webhook signatures is exposed to unauthenticated users. In typical secure implementations, such secrets are stored server-side and never transmitted or accessible via public endpoints. However, in this specific plugin version, the architectural design fails to restrict retrieval of this sensitive credential, allowing any external actor with network access to query the system and obtain the authentication token necessary for verifying webhook payloads.
This exposure directly undermines the security model designed to prevent tampering with payment confirmations. The plugin relies on HMAC signatures generated using this secret key to ensure that incoming notifications from the Bitcoin payment gateway are genuine and have not been altered in transit. Because attackers can retrieve the secret, they can locally compute valid signatures for arbitrary data payloads. This effectively neutralizes the signature verification process, as the system will accept forged requests that appear authentic due to their correct cryptographic validation tokens. The vulnerability represents a classic case of insecure direct object references or improper access control where sensitive configuration data is inadvertently made public through misconfigured endpoints or exposed source code logic.
The operational impact of this flaw allows unauthenticated attackers to forge payment-confirmation notifications with complete freedom over the transaction details. Specifically, an attacker can inject fake webhook events that record arbitrary donations as completed within the WordPress database. This includes specifying any desired donation amount, donor name, and accompanying message. Consequently, site administrators may be misled into believing that funds have been received when no actual cryptocurrency transactions occurred on the blockchain. This not only distorts financial reporting but also erodes trust among legitimate donors who expect their contributions to be accurately tracked and acknowledged by the platform operators.
From a classification perspective, this vulnerability aligns with CWE-284 Improper Access Control, as it involves failing to restrict access to sensitive information that should remain confidential. It also relates to CWE-345 Insufficient Verification of Data Authenticity because the system fails to ensure data originates from its claimed source due to the compromised secret key. In terms of attack vectors and tactics, this scenario maps closely to ATT&CK technique T1608 Link Exploitation for Impact or potentially T1190 Exploit Public-Facing Application if the exposure is via a web endpoint. The ability to forge transactions without authentication places it in the realm of high-severity integrity violations that require immediate remediation.
Mitigation strategies must focus on immediately restricting access to any endpoints or functions that expose the webhook secret key. Developers should ensure that such sensitive configuration values are stored securely, preferably outside of publicly accessible directories and never returned via API responses intended for unauthenticated users. Implementing strict server-side validation checks before processing webhooks is essential, ensuring that only requests originating from trusted IP ranges associated with the payment gateway are accepted, in addition to signature verification. Furthermore, rotating the webhook secret key immediately after patching will invalidate any previously forged tokens held by attackers who may have already harvested them during the window of vulnerability. Regular security audits and adherence to secure coding standards for handling cryptographic materials are recommended to prevent similar access control failures in future updates.