CVE-2026-2709 in busy
Summary
by MITRE • 02/19/2026
A flaw has been found in busy up to 2.5.5. The affected element is an unknown function of the file source-code/busy-master/src/server/app.js of the component Callback Handler. Executing a manipulation of the argument state can lead to open redirect. It is possible to launch the attack remotely. The exploit has been published and may be used. The project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 05/14/2026
This vulnerability resides within the busy project version 2.5.5, specifically within the Callback Handler component located in the source-code/busy-master/src/server/app.js file. The flaw manifests as an unknown function that processes argument state manipulation, creating an open redirect vulnerability that can be exploited remotely. The technical nature of this issue allows attackers to manipulate the state argument passed to the callback handler, potentially redirecting users to malicious websites without their knowledge. This type of vulnerability falls under the category of insecure redirection as classified by CWE-601, where applications redirect users to untrusted domains without proper validation. The vulnerability's remote exploitability means that attackers can initiate the malicious redirection from any location without requiring physical access to the target system, making it particularly dangerous in web-based environments. The fact that a working exploit has been published indicates that this vulnerability is not merely theoretical but represents an active threat that adversaries can leverage immediately.
The operational impact of this vulnerability extends beyond simple redirection attacks, as it can serve as a stepping stone for more sophisticated attacks such as phishing campaigns or credential theft operations. When users are redirected to malicious sites through this open redirect vulnerability, they may unknowingly provide sensitive information or download malware. The vulnerability's presence in the callback handler component suggests that it could affect authentication flows, session management, or other critical security mechanisms within the application. Attackers can craft malicious URLs that appear legitimate but redirect users to attacker-controlled domains, potentially bypassing security measures like URL filtering or user awareness training. The lack of response from the project maintainers despite early issue reporting creates a dangerous gap in security coverage, leaving users exposed to potential exploitation for extended periods. This delay in response aligns with ATT&CK technique T1068, where adversaries exploit existing vulnerabilities without proper patch management or security response procedures in place.
The remediation approach for this vulnerability requires immediate implementation of proper input validation and sanitization within the callback handler function. Developers should implement strict validation of redirect URLs to ensure they only allow redirection to trusted domains within the application's control. This approach aligns with security best practices outlined in OWASP Top 10 and the principle of least privilege in redirect handling. The solution involves implementing a whitelist of allowed domains or using a secure redirect mechanism that validates the target URL against a predefined set of trusted destinations. Additionally, the application should log all redirect attempts for security monitoring purposes and implement proper error handling to prevent information disclosure. Organizations should also consider implementing web application firewalls and security monitoring tools to detect and prevent exploitation attempts. The vulnerability demonstrates the critical importance of timely security patch management and the need for robust security response procedures that can quickly address reported issues before they are exploited in the wild.