CVE-2026-25526
📋 TL;DR
CVE-2026-25526 is a critical vulnerability in JinJava template engine that allows attackers to bypass sandbox restrictions and execute arbitrary Java code via ForTag manipulation. This affects all applications using vulnerable versions of JinJava to process untrusted template input. The vulnerability enables complete system compromise.
💻 Affected Systems
- HubSpot JinJava
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution leading to complete system takeover, data exfiltration, lateral movement, and persistent backdoor installation.
Likely Case
Arbitrary file read/write, sensitive data exposure, and potential remote code execution depending on application context.
If Mitigated
Limited impact if templates only process trusted input, but still poses risk if attack surface expands.
🎯 Exploit Status
Exploitation requires ability to inject or control template content. No public exploit code available yet.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.7.6 or 2.8.3
Vendor Advisory: https://github.com/HubSpot/jinjava/security/advisories/GHSA-gjx9-j8f8-7j74
Restart Required: Yes
Instructions:
1. Identify JinJava version in your application. 2. Update Maven/Gradle dependency to jinjava:2.7.6+ or jinjava:2.8.3+. 3. Rebuild and redeploy application. 4. Restart application server.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation to reject untrusted template content containing ForTag constructs.
Sandbox Enhancement
allConfigure JinJava with restrictive sandbox policies to limit class loading and file access.
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable applications from critical systems
- Deploy WAF rules to block suspicious template patterns and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Maven pom.xml or Gradle build.gradle for jinjava dependency version. If version <2.7.6 or between 2.8.0-2.8.2, system is vulnerable.Check Version:
mvn dependency:tree | grep jinjava OR gradle dependencies | grep jinjavaVerify Fix Applied:
Verify dependency version shows 2.7.6+ or 2.8.3+ in build configuration and deployed application.📡 Detection & Monitoring
Log Indicators:
- Unusual Java class loading patterns
- ForTag usage with suspicious parameters
- File system access from template engine context
Network Indicators:
- Outbound connections from application server to unexpected destinations
- Large data exfiltration patterns
SIEM Query:
source="application.logs" AND ("ForTag" OR "jinjava" OR "sandbox violation")🔗 References
- https://github.com/HubSpot/jinjava/commit/3d02e504d8bbb13bf3fe019e9ca7b51dfce7a998
- https://github.com/HubSpot/jinjava/commit/c7328dce6030ac718f88974196035edafef24441
- https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.7.6
- https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.8.3
- https://github.com/HubSpot/jinjava/security/advisories/GHSA-gjx9-j8f8-7j74
