CVE-2026-23835
📋 TL;DR
This vulnerability in LobeHub allows attackers to bypass file upload validation and quota limits by intercepting and modifying upload requests. Attackers can create arbitrary files in unintended paths and manipulate reported file sizes to exceed storage limits, potentially causing financial loss and service disruption. This affects all LobeHub instances running versions before 1.143.3.
💻 Affected Systems
- LobeHub
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete resource exhaustion leading to service unavailability, financial loss from unaccounted storage costs, and potential data corruption from arbitrary file creation.
Likely Case
Storage quota bypass allowing excessive uploads, distorted billing calculations, and degraded performance for legitimate users.
If Mitigated
Limited impact with proper network controls and monitoring, but still vulnerable to authenticated users.
🎯 Exploit Status
Exploitation requires user access to the file upload feature but uses simple request manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.143.3
Vendor Advisory: https://github.com/lobehub/lobehub/security/advisories/GHSA-wrrr-8jcv-wjf5
Restart Required: Yes
Instructions:
1. Update LobeHub to version 1.143.3 or later. 2. Restart the LobeHub service. 3. Verify the update was successful.
🔧 Temporary Workarounds
Disable File Upload Feature
allTemporarily disable the Knowledge Base file upload functionality until patching is complete.
Modify configuration to disable file uploads in the Knowledge Base module
Implement WAF Rules
allAdd web application firewall rules to validate and sanitize file upload requests.
Configure WAF to validate Content-Length headers and file upload parameters
🧯 If You Can't Patch
- Implement strict rate limiting on file upload endpoints
- Deploy network monitoring to detect abnormal upload patterns and size discrepancies
🔍 How to Verify
Check if Vulnerable:
Check if LobeHub version is below 1.143.3 and if file upload functionality is enabled.Check Version:
Check LobeHub admin panel or run appropriate version check command for your deployment method.Verify Fix Applied:
Confirm version is 1.143.3 or later and test file upload with manipulated size parameters to ensure validation occurs.📡 Detection & Monitoring
Log Indicators:
- Large discrepancies between reported file sizes and actual file sizes in upload logs
- Multiple upload requests from single user exceeding quota limits
- File creation in abnormal paths
Network Indicators:
- Unusually large file uploads with small reported sizes
- Modified Content-Length headers in upload requests
- High volume of upload requests from single IP
SIEM Query:
source="lobehub" AND (event="file_upload" AND (reported_size != actual_size OR path CONTAINS "../"))