CVE-2026-3813
📋 TL;DR
This CVE describes an injection vulnerability in opencc JFlow's Calculate function that allows remote attackers to execute malicious code or commands. The vulnerability affects all versions up to commit 5badc00db382d7cb82dad231e6a866b18e0addfe, and organizations using this workflow automation software are at risk.
💻 Affected Systems
- opencc JFlow
⚠️ 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
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Data manipulation, unauthorized access to sensitive information, or disruption of workflow processes.
If Mitigated
Limited impact with proper input validation and network segmentation in place.
🎯 Exploit Status
The exploit is publicly available and the vulnerability is in a core function, making exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown - vendor has not responded to disclosure
Vendor Advisory: None available
Restart Required: Yes
Instructions:
No official patch available. Monitor the project repository for updates and apply when available.
🔧 Temporary Workarounds
Input Validation Filter
allImplement strict input validation and sanitization for the Calculate function parameters
Implement input validation in src/main/java/bp/wf/httphandler/WF_CCForm.java
Network Segmentation
linuxRestrict network access to JFlow instances using firewalls or network policies
iptables -A INPUT -p tcp --dport [JFlow_port] -s [trusted_ips] -j ACCEPT
iptables -A INPUT -p tcp --dport [JFlow_port] -j DROP
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block injection patterns
- Disable or restrict access to the vulnerable Calculate function if not essential
🔍 How to Verify
Check if Vulnerable:
Check if your JFlow deployment uses code from commit 5badc00db382d7cb82dad231e6a866b18e0addfe or earlierCheck Version:
git log --oneline | head -20 (to check commit history)Verify Fix Applied:
Verify that input validation has been implemented in WF_CCForm.java and test with injection payloads📡 Detection & Monitoring
Log Indicators:
- Unusual parameter values in Calculate function calls
- Error messages containing injection patterns
- Unexpected process executions
Network Indicators:
- Unusual outbound connections from JFlow server
- Traffic patterns matching known exploit payloads
SIEM Query:
source="jflow.log" AND ("Calculate" AND ("|" OR "$" OR "{" OR "}" OR "runtime"))