CVE-2026-33330 in FileRise
Summary
by MITRE • 03/24/2026
FileRise is a self-hosted web file manager / WebDAV server. Prior to version 3.10.0, a broken access control issue in FileRise's ONLYOFFICE integration allows an authenticated user with read-only access to obtain a signed save callbackUrl for a file and then directly forge the ONLYOFFICE save callback to overwrite that file with attacker-controlled content. This issue has been patched in version 3.10.0.
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Analysis
by VulDB Data Team • 03/29/2026
The vulnerability CVE-2026-33330 represents a critical broken access control flaw within FileRise's integration with ONLYOFFICE, a popular collaborative office suite. This web-based file management system operates as a self-hosted solution with WebDAV capabilities, making it susceptible to unauthorized file manipulation when specific conditions are met. The issue specifically affects versions prior to 3.10.0, indicating that the developers identified and addressed this weakness in their security updates. The vulnerability resides in the interaction between FileRise's access control mechanisms and the ONLYOFFICE document editing integration, creating a path for privilege escalation through a carefully crafted attack vector that exploits the system's trust model.
The technical exploitation of this vulnerability involves an authenticated user who possesses only read-only permissions to leverage a flaw in the callback URL generation process. This user can obtain a signed save callback URL for a target file through legitimate access, then manipulate the ONLYOFFICE save callback mechanism to overwrite the file with malicious content. The flaw essentially allows unauthorized modification of files through a trusted integration channel, bypassing the normal access control restrictions that should prevent such operations. The attack requires the user to have existing authentication credentials and read access, but the vulnerability enables them to escalate their privileges to write access through the integration interface.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on FileRise for document management, as it allows for persistent data corruption and potential information disclosure. The ability to overwrite files with attacker-controlled content creates opportunities for malicious data manipulation, which could lead to complete document compromise or serve as a vector for further attacks within the system. The impact extends beyond simple file modification, as the attacker can potentially inject malicious content into documents that may be processed by other systems or users. This vulnerability particularly affects collaborative environments where multiple users access shared documents through the WebDAV interface.
The mitigation strategy for this vulnerability involves upgrading to FileRise version 3.10.0 or later, which implements proper access control validation for the ONLYOFFICE integration callbacks. Organizations should also consider implementing additional monitoring for suspicious file modification patterns and review access control policies to ensure users only have necessary permissions. Security practitioners should examine the integration points between FileRise and external services like ONLYOFFICE to identify similar access control weaknesses that may exist in other third-party integrations. This vulnerability aligns with CWE-284, which addresses improper access control, and represents a classic example of how trusted integration points can become attack vectors when proper validation is not implemented. The ATT&CK framework would classify this as a privilege escalation technique through access control bypass, potentially leading to data integrity compromise and persistent access within the system. Organizations should also consider implementing network segmentation and access controls around file management systems to limit the impact of such vulnerabilities in the event of successful exploitation.