CVE-2025-70023: Transloadit Uppy Auth Bypass Vulnerability

CVE-2025-70023 Overview

A critical type confusion vulnerability (CWE-843: Access of Resource Using Incompatible Type) has been discovered in Transloadit Uppy version 0.25.6. This vulnerability allows attackers to access resources using an incompatible type, potentially leading to memory corruption, arbitrary code execution, or denial of service conditions.

Uppy is a popular open-source JavaScript file uploader that integrates with various storage backends. The type confusion flaw in this version could allow remote attackers to manipulate the application's memory handling, compromising the confidentiality, integrity, and availability of affected systems.

Critical Impact

This type confusion vulnerability enables remote attackers to potentially execute arbitrary code, corrupt memory, or cause denial of service without requiring authentication or user interaction.

Affected Products

• Transloadit Uppy v0.25.6
• Applications integrating vulnerable Uppy versions
• Web applications using affected Uppy file upload components

Discovery Timeline

• 2026-04-14 - CVE-2025-70023 published to NVD
• 2026-04-16 - Last updated in NVD database

Technical Details for CVE-2025-70023

Vulnerability Analysis

The vulnerability stems from a type confusion issue (CWE-843) in Transloadit Uppy v0.25.6. Type confusion vulnerabilities occur when a program accesses a resource using an incompatible type, leading to undefined behavior. In the context of a JavaScript-based file uploader like Uppy, this could manifest during file processing, data serialization, or when handling plugin communications.

When an attacker exploits this vulnerability, the application may interpret data using an incorrect type assumption. This can lead to memory corruption scenarios where object properties or methods are accessed incorrectly, potentially allowing an attacker to manipulate program flow or access sensitive memory regions.

The vulnerability is exploitable over the network without requiring authentication or user interaction, making it particularly dangerous for publicly accessible web applications that utilize the affected Uppy component.

Root Cause

The root cause is an improper type check or missing type validation within the Uppy codebase at version 0.25.6. When processing certain inputs or internal data structures, the application fails to properly verify that objects conform to expected types before accessing their properties or methods. This allows an attacker to supply malformed data that the application processes under incorrect type assumptions.

Attack Vector

The vulnerability is exploitable via a network-based attack vector. An attacker can craft malicious requests or file upload payloads designed to trigger the type confusion condition. The attack does not require prior authentication or any user interaction, allowing for automated exploitation against vulnerable Uppy deployments.

The attack flow typically involves:

1. Identifying a web application using vulnerable Uppy v0.25.6
2. Crafting a malicious payload that triggers the type confusion
3. Sending the payload to the target application's file upload endpoint
4. Exploiting the resulting memory corruption for code execution or denial of service

Technical details and a proof-of-concept can be found in the GitHub Gist PoC Repository.

Detection Methods for CVE-2025-70023

Indicators of Compromise

• Unusual file upload requests with malformed or unexpected data types in request payloads
• Application crashes or errors in Uppy-related JavaScript execution
• Memory-related exceptions or unexpected behavior in file processing workflows
• Anomalous network traffic patterns targeting file upload endpoints

Detection Strategies

• Monitor application logs for JavaScript errors or exceptions related to Uppy file upload processing
• Implement web application firewall (WAF) rules to detect malformed file upload requests
• Deploy runtime application self-protection (RASP) to detect type confusion exploitation attempts
• Use SentinelOne Singularity Platform to monitor for anomalous process behavior and memory corruption indicators

Monitoring Recommendations

• Enable verbose logging for file upload components and monitor for type-related errors
• Implement application performance monitoring to detect unusual processing patterns
• Set up alerts for crashes or restarts of services handling file uploads
• Review network traffic for payloads matching known exploitation patterns

How to Mitigate CVE-2025-70023

Immediate Actions Required

• Audit your applications to identify any instances using Transloadit Uppy v0.25.6
• Update Uppy to a patched version that addresses the type confusion vulnerability
• Implement input validation at the network perimeter to filter malicious payloads
• Consider temporarily disabling file upload functionality if patches are unavailable

Patch Information

Organizations should upgrade to a patched version of Transloadit Uppy. Check the official Transloadit Uppy Project for the latest security updates and release notes. Monitor the vendor repository for security advisories related to this vulnerability.

Workarounds

• Implement strict input validation and type checking before data reaches Uppy components
• Deploy a web application firewall with rules to block potentially malicious file upload payloads
• Isolate file upload functionality in sandboxed environments to limit exploitation impact
• Restrict network access to file upload endpoints where possible using network segmentation