CVE-2025-66908
📋 TL;DR
This vulnerability allows attackers to upload arbitrary files including executables, scripts, or web shells by bypassing file type validation in Turms AI-Serving's OCR functionality. The system only checks Content-Type headers and file extensions without validating actual file content. Organizations using Turms AI-Serving module v0.10.0-SNAPSHOT or earlier are affected.
💻 Affected Systems
- Turms AI-Serving module
📦 What is this software?
Turms by Turms Im
⚠️ Risk & Real-World Impact
Worst Case
Server-side code execution leading to complete system compromise, data exfiltration, or ransomware deployment.
Likely Case
Upload of malicious files leading to stored XSS, information disclosure, or limited file system access.
If Mitigated
File uploads blocked or quarantined with no impact on system integrity.
🎯 Exploit Status
Exploitation requires access to upload endpoint but no authentication bypass needed. Public report includes technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not yet released
Vendor Advisory: https://github.com/turms-im/turms
Restart Required: Yes
Instructions:
1. Monitor Turms GitHub repository for security updates. 2. Apply patch when available. 3. Restart Turms AI-Serving service.
🔧 Temporary Workarounds
Implement server-side file validation
allAdd magic byte validation to OcrController to check actual file signatures
Modify OcrController.java to include file signature validation using libraries like Apache Tika or custom validation
Restrict file upload endpoints
allUse web application firewall or reverse proxy to block suspicious uploads
Configure WAF rules to validate Content-Type matches actual file content
Set up reverse proxy to scan uploaded files
🧯 If You Can't Patch
- Disable OCR image upload functionality entirely if not required
- Implement strict file extension whitelisting and size limits at network perimeter
🔍 How to Verify
Check if Vulnerable:
Attempt to upload a non-image file with Content-Type: image/jpeg header to OCR endpoint. If accepted, system is vulnerable.Check Version:
Check pom.xml or build.gradle for turms-ai-serving version, or run: java -jar turms-ai-serving.jar --versionVerify Fix Applied:
Test file upload with mismatched Content-Type and actual file content. Validated systems should reject such uploads.📡 Detection & Monitoring
Log Indicators:
- File uploads with mismatched Content-Type and file extensions
- Large number of failed/successful upload attempts
- Uploads of non-image file types to OCR endpoints
Network Indicators:
- HTTP POST requests to /ocr/upload with suspicious Content-Type headers
- Uploads of executable files to image endpoints
SIEM Query:
source="turms-ai-serving" AND (url_path="/ocr/upload" OR url_path="/api/ocr") AND (content_type!="image/*" OR file_extension IN [".exe", ".php", ".jsp", ".sh"])🔗 References
- https://github.com/Xzzz111/public_cve_report/blob/main/CVE-2025-66908_report.md
- https://github.com/turms-im/turms
- https://github.com/turms-im/turms/blob/develop/turms-ai-serving/src/main/java/im/turms/ai/domain/ocr/controller/OcrController.java
- https://github.com/Xzzz111/public_cve_report/blob/main/CVE-2025-66908_report.md
