CVE-2026-1126
Unrestricted File Upload in lwj Flow SVG File Handler
Publication date: 2026-01-18
Last updated on: 2026-04-29
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| unknown_vendor | flowable | 1.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-434 | The product allows the upload or transfer of dangerous file types that are automatically processed within its environment. |
| CWE-284 | The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-1126 is an arbitrary file upload vulnerability in the Flowable project, specifically in the uploadFile function of FormResource.java. The vulnerability arises because the system does not properly validate or sanitize the file extensions and Content-Type headers during file uploads. This allows attackers to upload malicious files such as HTML, SVG, or executable files remotely without authentication. These malicious files can be used to execute stored Cross-Site Scripting (XSS) attacks, steal administrator session tokens, perform lateral movement within the system, or potentially execute remote code. The root cause is insecure validation in the file upload mechanism, making it a critical security design flaw. [1, 2, 3]
How can this vulnerability impact me? :
This vulnerability can impact you by allowing attackers to upload arbitrary and potentially dangerous files to your system remotely without authentication. Exploiting this flaw can lead to stored Cross-Site Scripting (XSS) attacks, theft of administrator session tokens, lateral movement within your network, and possibly remote code execution. This compromises the confidentiality, integrity, and availability of your system, potentially leading to unauthorized access, data breaches, and system disruption. [1, 2, 3]
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring for HTTP POST requests to the endpoint `/front/flow/uploadFile/` that include file uploads with suspicious or unexpected file extensions or content types. You can use network monitoring tools or web server logs to identify such requests. For example, using command-line tools like `curl` to test the endpoint or `grep` to search logs for POST requests to `/front/flow/uploadFile/`. A sample detection command could be: `grep 'POST /front/flow/uploadFile/' /var/log/nginx/access.log` to find upload attempts. Additionally, inspecting uploaded files for unexpected extensions (e.g., `.exe`, `.html`, `.svg`) can help detect exploitation attempts. [1, 3]
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include disabling or restricting access to the vulnerable file upload endpoint `/front/flow/uploadFile/` to prevent arbitrary file uploads. Since no official patch or vendor response is available, consider implementing additional validation on the server side to check file extensions and Content-Type headers before accepting uploads. Alternatively, replace the affected component with a secure alternative. Monitoring and blocking suspicious upload attempts via web application firewalls (WAF) or network security tools is also recommended. [2]
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows attackers to upload arbitrary and potentially malicious files, which can lead to stored Cross-Site Scripting (XSS) attacks, theft of administrator session tokens, and lateral movement within the system. This compromises the confidentiality, integrity, and availability of the affected system. Such security breaches can result in unauthorized access to sensitive data, potentially violating compliance requirements under standards like GDPR and HIPAA that mandate protection of personal and health information. Therefore, this vulnerability negatively impacts compliance with these common standards and regulations by exposing systems to data breaches and unauthorized data access. [1, 2, 3]