CVE-2026-57489 in FileRise
Summary
by MITRE • 10/15/2026
FileRise is a self-hosted web-based file manager with multi-file upload, editing, and batch operations. Prior to 3.16.0, FileRise deployments with AUTH_BYPASS enabled trust the configured reverse-proxy identity header without verifying that the request originated from FR_TRUSTED_PROXIES. When the backend application port is reachable directly, an unauthenticated attacker can supply X-Remote-User and obtain a session for the asserted account, including an administrator account, without a password or MFA. The flaw is limited to deployments that enable proxy-header authentication and expose an untrusted path to the backend. This issue is fixed in version 3.16.0.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in FileRise prior to version 3.16.0 represents a critical identity management flaw rooted in improper validation of reverse proxy headers, specifically categorized under CWE-287 Improper Authentication and CWE-434 Unrestricted Upload of File with Dangerous Type when considering the broader context of administrative access abuse. This self-hosted web-based file manager supports multi-file upload, editing, and batch operations, relying heavily on accurate user identity for access control decisions. The core technical flaw occurs in deployments where the AUTH_BYPASS configuration option is enabled alongside a misconfigured network topology that exposes the backend application port directly to untrusted networks or allows direct client connections bypassing the reverse proxy layer. In such scenarios, the application trusts the X-Remote-User header provided by the client without verifying whether the request actually originated from one of the trusted proxies listed in FR_TRUSTED_PROXIES. This lack of source IP verification effectively nullifies the authentication mechanism for any user who can send HTTP requests directly to the backend service.
From an operational perspective, this flaw allows unauthenticated attackers to impersonate any existing user account by simply setting the X-Remote-User header to a desired username during their request. Because FileRise relies on these headers for session creation when AUTH_BYPASS is active, supplying this header results in the application issuing a valid authentication session cookie or token associated with the asserted identity. This bypasses all standard password-based login procedures and multi-factor authentication (MFA) requirements that would normally be enforced by the upstream reverse proxy or external identity provider. The impact is particularly severe when an attacker targets administrator accounts, as gaining access to such identities provides full control over file operations, user management settings, and potentially sensitive data stored within the system. This aligns with MITRE ATT&CK technique T1078 Valid Accounts, where adversaries leverage legitimate credentials or identity artifacts to maintain persistent access without detection by traditional authentication monitoring tools.
The scope of this vulnerability is strictly limited to specific deployment configurations that enable proxy-header authentication while simultaneously failing to restrict direct backend access through network segmentation or firewall rules. Deployments that do not use AUTH_BYPASS are unaffected, as they rely on standard credential verification flows handled internally rather than trusting external headers for identity assertion. However, in environments where reverse proxies like Nginx or Apache are used to offload SSL termination and authentication, administrators may incorrectly assume that the backend is secure because it sits behind a proxy. The failure lies in not enforcing strict source IP validation on the backend service itself, assuming all incoming requests have already been authenticated by the upstream layer. This architectural assumption creates an attack vector for any entity capable of reaching the backend port directly, including compromised internal hosts or external attackers if network boundaries are misconfigured.
To mitigate this vulnerability, organizations must upgrade to FileRise version 3.16.0 or later, where the logic has been corrected to strictly validate that requests originate from trusted proxy IPs before accepting identity headers. For deployments unable to immediately patch due to operational constraints, immediate remediation steps include ensuring that FR_TRUSTED_PROXIES is correctly configured with all legitimate reverse proxy IP addresses and verifying network firewall rules to prevent direct access to the backend application port from untrusted networks or the public internet. Additionally, administrators should audit their deployment architecture to ensure no alternative paths exist for clients to bypass the authentication layer provided by the reverse proxy. Implementing strict egress filtering on the server hosting FileRise can further reduce risk by ensuring that only designated proxy servers can communicate with the backend service port. Regular security assessments and penetration testing of web application architectures are recommended to identify similar misconfigurations in other services relying on header-based authentication mechanisms.