CVE-2026-33527 in parse-server
Summary
by MITRE • 03/24/2026
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.57 and 9.6.0-alpha.48, an authenticated user can overwrite server-generated session fields such as expiresAt and createdWith when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent. This issue has been patched in versions 8.6.57 and 9.6.0-alpha.48.
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Analysis
by VulDB Data Team • 03/29/2026
The vulnerability identified as CVE-2026-33527 affects Parse Server, a popular open-source backend framework designed for deployment on Node.js infrastructure. This authentication flaw specifically targets the session management mechanism within the platform's REST API implementation. The issue manifests when authenticated users attempt to update their own session records through the application programming interface, creating a scenario where legitimate session attributes can be manipulated by authorized individuals. The vulnerability represents a significant security weakness in the platform's access control and session validation processes, potentially allowing unauthorized persistence of user sessions beyond their intended expiration periods.
The technical flaw stems from inadequate input validation and field protection mechanisms within the session update functionality. When users submit session update requests through the REST API, the system fails to properly validate or restrict modification of server-generated session fields including expiresAt and createdWith timestamps. This validation failure occurs because the application does not distinguish between user-provided data and system-generated attributes during the update process. The vulnerability is classified under CWE-284 Access Control Bypass, specifically manifesting as improper access control over session management components. The flaw allows an authenticated attacker to manipulate session metadata that should remain immutable, effectively circumventing the platform's built-in session lifetime enforcement mechanisms.
The operational impact of this vulnerability extends beyond simple session persistence concerns, creating substantial risks for system security and user privacy. An attacker who successfully exploits this vulnerability can maintain access to the system indefinitely, bypassing all configured session timeout policies and potentially gaining prolonged unauthorized access to protected resources. This persistent access capability enables extended surveillance, data exfiltration, and privilege escalation attacks that would otherwise be prevented by normal session expiration mechanisms. The vulnerability particularly affects environments where session timeouts are configured to enforce strict access controls, as the attacker can effectively neutralize these security measures. This issue aligns with ATT&CK technique T1566.002 Credential Stuffing and T1078 Valid Accounts, as it allows for prolonged unauthorized access through legitimate authenticated sessions.
The mitigation strategy involves upgrading to Parse Server versions 8.6.57 or 9.6.0-alpha.48, which contain the necessary patches to address the session field validation issue. Organizations should implement immediate remediation by updating their Parse Server installations to the patched versions and conducting thorough security assessments of their session management configurations. Security teams should also review existing session policies and consider implementing additional monitoring for unusual session update patterns that might indicate exploitation attempts. The patched versions include enhanced input validation that properly separates user-modifiable fields from system-generated attributes, ensuring that session metadata such as expiration timestamps cannot be manipulated by authenticated users. Organizations should also consider implementing session lifecycle monitoring and alerting mechanisms to detect potential exploitation attempts and maintain compliance with security standards such as NIST SP 800-53 control CM-7 Configuration Settings.