CVE-2026-111278 in NivoCart
Summary
by MITRE • 10/16/2026
NivoCart through 2.5.1 contains a CAPTCHA bypass vulnerability that allows unauthenticated attackers to defeat form protection because the expected code is printed as plain text in the HTML. Attackers can fetch protected forms, extract the captcha_image value with a pattern match, and submit it to automate spam, registrations, reviews, and account deletion requests.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability identified in NivoCart versions through 2.5.1 represents a critical failure in implementing security controls designed to prevent automated abuse of web forms. Specifically, the application suffers from an improper implementation of CAPTCHA mechanisms, which are intended to distinguish between human users and automated scripts or bots. In this flawed architecture, the system generates a challenge-response token but fails to obscure it effectively within the client-side code. Instead of rendering the captcha value as part of an image that requires optical character recognition or keeping it strictly server-side for validation against user input, the application prints the expected CAPTCHA code directly in plain text within the HTML source. This design flaw fundamentally undermines the purpose of the protection mechanism by making the secret trivially accessible to any entity capable of parsing HTTP responses.
From a technical perspective, this issue is classified under CWE-798 as Use of Hard-coded Credentials or Secrets, although it more specifically aligns with CWE-614 Sensitive Cookie in HTTPS Session Without Secure Attribute if viewed through session management lenses, but primarily falls under CWE-200 Exposure of Sensitive Information to an Unauthorized Actor. The vulnerability allows unauthenticated attackers to interact with protected endpoints without possessing valid credentials or solving complex challenges. By fetching the HTML content of any form protected by this CAPTCHA implementation, an attacker can employ simple pattern matching algorithms to extract the captcha_image value directly from the DOM structure. Once extracted, this value is submitted alongside other form data during subsequent POST requests, effectively bypassing the intended human verification step.
The operational impact of this vulnerability is severe and multifaceted, affecting the integrity and availability of services provided by NivoCart installations. Because the CAPTCHA protection is rendered ineffective, malicious actors can automate a wide range of abusive activities with minimal effort and cost. These include mass registration of fake user accounts, which can be used for further phishing campaigns or to create botnets. Additionally, attackers can flood public-facing forms with spam reviews, degrading the quality of content and potentially misleading legitimate customers. The vulnerability also enables automated account deletion requests, posing a direct threat to data integrity and availability by allowing unauthorized users to remove critical accounts without proper authentication checks. This level of automation significantly lowers the barrier for entry for low-skilled attackers who previously would have been blocked by more robust CAPTCHA implementations like reCAPTCHA or hCaptcha.
To mitigate this vulnerability, immediate action is required from system administrators and developers maintaining NivoCart instances up to version 2.5.1. The most effective remediation strategy involves upgrading the application to a patched version where the CAPTCHA implementation has been corrected to ensure that challenge codes are not exposed in plain text within HTML responses. If an upgrade is not immediately feasible, temporary mitigations should be implemented at the web server or firewall level. This includes implementing rate limiting on form submission endpoints to detect and block high-volume automated requests regardless of whether they pass the CAPTCHA check. Additionally, deploying a Web Application Firewall with rules specifically targeting patterns associated with this vulnerability can help filter out malicious traffic attempting to exploit the exposed captcha_image parameter until the underlying code is fixed.
This incident highlights the importance of adhering to secure coding practices regarding authentication and authorization controls as outlined in industry standards such as OWASP Top 10, particularly under categories related to Broken Access Control and Security Misconfiguration. The ATT&CK framework categorizes this type of exploitation under Tactic TA0004: Privilege Escalation or TA0005: Defense Evasion, specifically leveraging techniques that bypass security features designed to prevent automated abuse. By addressing the root cause—the exposure of sensitive validation tokens in client-side code—organizations can restore the intended level of protection against automated threats and ensure the integrity of their e-commerce platforms.