CVE-2026-61843 in FileRise
Summary
by MITRE • 10/14/2026
FileRise is a self-hosted web-based file manager with multi-file upload, editing, and batch operations. Prior to 3.18.0, FileRise upload-enabled shared-folder and upload-only links do not reject a destination filename that already exists. An unauthenticated visitor with a valid share token and any configured share password can upload a file with the same name as an existing file and silently replace its content while the original uploader metadata remains. The same replacement gap affects ordinary authenticated uploads through /api/upload/upload.php and authenticated upload-only users who lack edit authority over the existing file. This issue is fixed in version 3.18.0.
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Analysis
by VulDB Data Team • 10/15/2026
FileRise is a self-hosted web-based application designed to facilitate multi-file uploading, editing, and batch operations for user communities. The software provides mechanisms for sharing files via shared folders and upload-only links, which are intended to allow specific users or unauthenticated visitors to contribute content without granting full administrative access. These features rely on share tokens and optional passwords to authenticate requests and authorize file uploads into designated directories.
A critical vulnerability exists in versions prior to 3.18.0 regarding the handling of destination filenames during upload operations. The application fails to reject a request when an uploaded file has the same name as an existing file within the target directory. Instead of returning an error or prompting for overwrite confirmation, the system silently replaces the content of the existing file with the newly uploaded data. This behavior occurs regardless of whether the operation is performed through upload-enabled shared folders, upload-only links, or standard authenticated uploads via the /api/upload/upload.php endpoint.
The security implications of this flaw are significant because it allows for unauthorized modification of stored files without proper authorization checks. An unauthenticated visitor possessing a valid share token and any configured share password can exploit this gap to overwrite existing content. Similarly, authenticated users who have upload-only permissions but lack edit authority over the target file can also trigger this silent replacement. In all cases, while the file data is replaced, the original uploader metadata remains unchanged, creating a discrepancy between the actual content owner and the recorded authorship information. This undermines data integrity and auditability, as it becomes difficult to determine who originally uploaded specific files or when they were last legitimately modified by an authorized editor.
This vulnerability aligns with CWE-354, which describes improper validation of metadata in file uploads, specifically regarding the lack of checks for existing filenames that could lead to unintended overwrites. From a tactical perspective, this behavior can be leveraged in attacks categorized under ATT&CK technique T1083, File and Directory Discovery, or more accurately T1564, Hidden Files and Directories if used to obscure malicious content by replacing legitimate files silently. It also relates to CWE-276, Incorrect Default Permissions, as the system defaults to an overwrite behavior that may not align with user expectations for data preservation.
To mitigate this risk, organizations using FileRise must upgrade immediately to version 3.18.0 or later, where the issue has been resolved by implementing proper checks to prevent silent overwrites of existing files. Until upgrading is possible, administrators should review upload permissions and consider restricting access to shared folders to trusted users only. Additionally, enabling detailed logging for file operations can help detect instances of unauthorized content replacement through metadata anomalies. Regular integrity checks on stored files are also recommended to identify any discrepancies between expected and actual file contents caused by this vulnerability.