CVE-2026-54563 in Cloudreve
Summary
by MITRE • 07/15/2026
Cloudreve is a self-hosted file management and sharing system. Prior to 4.16.1, a Cloudreve WebDAV account rooted at a configured folder can send paths such as /dav/%2e%2e/outside.txt because stripPrefix in pkg/webdav/webdav.go joins the decoded request suffix to the account root with fs.URI.JoinRaw without checking containment, allowing the scoped credential to read and list files outside the configured folder and writable credentials to create, overwrite, move, or delete them. This issue is reported as fixed in version 4.16.1.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical path traversal flaw in Cloudreve's WebDAV implementation that enables unauthorized access beyond the designated file scope. The vulnerability exists in the handling of URL-encoded paths within the WebDAV subsystem where the stripPrefix function processes requests without proper containment validation. When a WebDAV account is configured with a specific root folder, the system should maintain strict boundaries to prevent users from accessing files outside this configured scope. However, the flaw allows malicious actors to manipulate request paths using encoded dot-sequence characters such as %2e%2e which decode to .. sequences that can navigate upward in the directory structure.
The technical implementation issue stems from the pkg/webdav/webdav.go file where fs.URI.JoinRaw function is called without validating whether the resulting path remains within the account's configured root directory. This design flaw creates a privilege escalation vulnerability where authenticated users with read access can enumerate and retrieve files from outside their designated folder scope. Similarly, users with write permissions can exploit this weakness to create, modify, move, or delete files in directories beyond their authorized boundaries, effectively bypassing the intended access controls.
The operational impact of this vulnerability is severe as it completely undermines the security model of Cloudreve's file management system. An attacker with even basic WebDAV credentials could potentially discover sensitive files stored outside the intended scope, leading to data leakage and unauthorized information disclosure. Write privileges enable more destructive actions including creating malicious files, overwriting legitimate documents, or deleting critical system files that may exist outside the configured folder boundaries.
This vulnerability aligns with CWE-22 Path Traversal and CWE-352 Cross-Site Request Forgery patterns, representing a classic case of inadequate input validation and insufficient access control enforcement. The issue maps to ATT&CK technique T1078 Valid Accounts for maintaining persistent access and T1566 Phishing for initial compromise. Organizations using Cloudreve versions prior to 4.16.1 should immediately implement mitigations including mandatory path validation, strict URI decoding checks, and comprehensive access control reviews. The fix implemented in version 4.16.1 addresses the root cause by enforcing proper containment checks before joining paths, ensuring that all WebDAV operations remain within the configured account scope and preventing unauthorized directory traversal attacks.