CVE-2025-59340
📋 TL;DR
CVE-2025-59340 is a critical deserialization vulnerability in jinjava that allows attackers to bypass sandbox restrictions and instantiate arbitrary Java classes. This enables file system access and potentially remote code execution. All systems using jinjava versions prior to 2.8.1 are affected.
💻 Affected Systems
- HubSpot jinjava
📦 What is this software?
Jinjava by Hubspot
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, and lateral movement within the network.
Likely Case
File system access allowing reading of sensitive files like /etc/passwd, configuration files, and potentially credential theft.
If Mitigated
Limited impact if proper input validation and sandboxing are in place, though the vulnerability bypasses existing sandbox controls.
🎯 Exploit Status
Exploitation requires template injection vector but doesn't require authentication. The vulnerability bypasses existing sandbox controls.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.1
Vendor Advisory: https://github.com/HubSpot/jinjava/security/advisories/GHSA-m49c-g9wr-hv6v
Restart Required: Yes
Instructions:
1. Update jinjava dependency to version 2.8.1 or later. 2. Update pom.xml or build.gradle to use jinjava:2.8.1+. 3. Rebuild and redeploy application. 4. Restart affected services.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation on all template inputs to prevent injection of malicious template code.
Java Security Manager Restrictions
allConfigure Java Security Manager with strict permissions to limit what classes can be instantiated.
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems from sensitive resources.
- Deploy web application firewall (WAF) rules to detect and block template injection attempts.
🔍 How to Verify
Check if Vulnerable:
Check your project's dependency management file (pom.xml, build.gradle) for jinjava version. If version is <2.8.1, you are vulnerable.Check Version:
mvn dependency:tree | grep jinjava OR gradle dependencies | grep jinjavaVerify Fix Applied:
After updating, verify that jinjava version is 2.8.1 or higher in your dependency management file and that the application builds successfully.📡 Detection & Monitoring
Log Indicators:
- Unusual template processing errors
- Attempts to access file:// URLs in template contexts
- Class instantiation errors for unexpected classes
Network Indicators:
- HTTP requests containing suspicious template syntax
- Outbound connections to unexpected URLs from template processing
SIEM Query:
source="application.logs" AND ("jinjava" OR "template engine") AND ("error" OR "exception") AND ("deserialization" OR "URL" OR "file://")