CVE-2026-53992 in ProjectSend
Summary
by MITRE • 08/05/2026
ProjectSend r2029 contains a reflected cross-site scripting vulnerability in thumbnails-regenerate.php that allows remote attackers to inject arbitrary HTML and JavaScript by supplying unsanitized values in the start_date and end_date GET parameters, which are echoed unescaped into HTML attribute values. Attackers can craft a malicious URL that, when followed by an authenticated victim with edit_settings permissions, executes injected scripts in the application origin to steal session cookies or perform unauthorized actions including user management, file management, and application settings changes.
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Analysis
by VulDB Data Team • 08/06/2026
The ProjectSend vulnerability identified in r2029 represents a critical reflected cross-site scripting flaw that undermines the security of the web-based file sharing platform. This vulnerability exists within the thumbnails-regenerate.php component where user-supplied input values are inadequately sanitized before being rendered in HTML contexts. The specific weakness allows attackers to manipulate the start_date and end_date parameters through GET requests, creating a pathway for malicious code injection that can persist across user sessions.
The technical implementation of this vulnerability stems from improper input validation and output encoding practices within the application's data handling pipeline. When legitimate users access the thumbnails regeneration functionality with crafted malicious parameters, the system fails to escape special characters in the echoed values, thereby allowing HTML attributes to be manipulated. This reflects a fundamental breakdown in the application's security architecture that violates established secure coding principles and industry standards such as CWE-79 which specifically addresses cross-site scripting vulnerabilities.
The operational impact of this vulnerability extends beyond simple script execution, creating a vector for session hijacking and privilege escalation attacks. An attacker who successfully convinces an authenticated user with edit_settings permissions to click a maliciously crafted URL can execute arbitrary JavaScript within the victim's browser context. This opens the door to stealing session cookies, which can then be used to impersonate legitimate users and gain unauthorized access to sensitive system resources including user management controls, file repositories, and application configuration settings.
The security implications of this vulnerability align with ATT&CK technique T1531 which focuses on establishing persistence through malicious scripts, and T1078 which covers legitimate credential use for unauthorized access. Organizations running ProjectSend r2029 should immediately implement input sanitization measures including proper HTML escaping of all user-supplied parameters before rendering them in web responses. The fix requires comprehensive parameter validation that strips or encodes potentially dangerous characters while maintaining application functionality.
Mitigation strategies should include implementing Content Security Policy headers to limit script execution contexts, deploying web application firewalls to detect and block malicious requests, and conducting regular security audits of input handling mechanisms. Additionally, organizations must ensure proper user permission controls are enforced through role-based access controls that limit the scope of actions available to authenticated users. The vulnerability demonstrates the critical importance of defense-in-depth strategies where multiple layers of security controls work together to prevent successful exploitation attempts.
Security teams should prioritize patching this vulnerability as a high-priority remediation task, particularly in environments where ProjectSend is deployed with administrative user accounts that have elevated privileges. Regular security testing including dynamic application security testing and manual penetration testing should be implemented to identify similar vulnerabilities in other components of the application stack. The incident underscores the necessity of continuous security monitoring and proactive vulnerability management practices to maintain robust protection against evolving threat landscapes.
Organizations utilizing ProjectSend or similar file sharing platforms must recognize that reflected XSS vulnerabilities serve as gateways for more sophisticated attacks including credential theft, data exfiltration, and system compromise operations. The attack surface expands when considering that authenticated users with appropriate permissions can inadvertently facilitate these attacks, making user education and security awareness programs essential components of comprehensive defense strategies.