CVE-2026-7306: Xuxueli xxl-job RCE Vulnerability

CVE-2026-7306 Overview

CVE-2026-7306 is a hard-coded cryptographic key vulnerability affecting Xuxueli xxl-job, a distributed task scheduling platform, in versions up to and including 3.3.2. The vulnerability exists in the OpenAPI Endpoint component, specifically within the file xxl-job-admin/src/main/java/com/xxl/job/admin/scheduler/openapi/OpenApiController.java. The flaw involves the default_token argument, which uses a hard-coded cryptographic key that could allow attackers to bypass authentication mechanisms or forge valid tokens.

Critical Impact

Remote attackers can potentially exploit the hard-coded default token to gain unauthorized access to the xxl-job admin interface, potentially allowing task manipulation, job scheduling interference, or information disclosure across distributed systems.

Affected Products

• Xuxueli xxl-job versions up to 3.3.2
• xxl-job-admin component with OpenAPI Endpoint enabled
• Systems using default token configuration without modification

Discovery Timeline

• 2026-04-28 - CVE CVE-2026-7306 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-7306

Vulnerability Analysis

This vulnerability stems from the use of a hard-coded cryptographic key (CWE-320) in the xxl-job OpenAPI authentication mechanism. The OpenApiController.java file contains a static default_token value that is used for API authentication. When this default value is not changed during deployment, any attacker with knowledge of this token can authenticate to the OpenAPI endpoints without proper authorization.

The attack is remotely exploitable over the network, though it requires high complexity to successfully exploit. The difficulty lies in the attacker needing to identify vulnerable instances and understand the API structure. However, since the exploit has been publicly disclosed, the barrier to exploitation is reduced for motivated attackers.

Root Cause

The root cause of this vulnerability is the implementation of a static, hard-coded default authentication token within the OpenAPI controller. Rather than generating unique tokens during installation or requiring administrators to configure custom tokens before deployment, the application ships with a predictable default value. This violates secure coding principles that mandate dynamic, environment-specific cryptographic material.

Attack Vector

The attack vector is network-based, allowing remote exploitation without requiring any user interaction or prior authentication. An attacker can target the OpenAPI endpoint directly by:

1. Identifying xxl-job instances exposed to the network
2. Locating the OpenAPI endpoint at the known path
3. Using the hard-coded default token to authenticate API requests
4. Executing privileged operations through the authenticated API session

The vulnerability allows for limited confidentiality, integrity, and availability impacts when successfully exploited. Attackers may be able to read sensitive job configurations, modify scheduled tasks, or disrupt normal job execution workflows.

Detection Methods for CVE-2026-7306

Indicators of Compromise

• Unexpected API authentication attempts to the /openapi/ endpoint with default token values
• Unusual job creation, modification, or deletion activity through the OpenAPI interface
• Authentication logs showing successful API access from unknown or suspicious IP addresses
• Modifications to scheduled tasks or job configurations without corresponding administrative actions

Detection Strategies

• Monitor authentication logs for OpenAPI endpoint access patterns and flag repeated successful authentications from external sources
• Implement network intrusion detection rules to identify requests containing known default token patterns
• Audit xxl-job configuration files to verify that default_token has been changed from the default value
• Deploy application firewall rules to inspect and log all traffic to xxl-job OpenAPI endpoints

Monitoring Recommendations

• Enable detailed logging for all OpenAPI controller activities and forward logs to centralized SIEM systems
• Set up alerts for any API authentication from IP addresses outside the expected administrative ranges
• Regularly review job execution history for anomalies that could indicate unauthorized manipulation
• Implement runtime application self-protection (RASP) to detect exploitation attempts

How to Mitigate CVE-2026-7306

Immediate Actions Required

• Immediately change the default_token value to a unique, cryptographically strong random string
• Restrict network access to the OpenAPI endpoint using firewall rules or network segmentation
• Audit existing job configurations and execution logs for signs of unauthorized access
• Consider disabling the OpenAPI endpoint entirely if not required for operations

Patch Information

At the time of publication, administrators should monitor the GitHub XXL-Job Repository for official patches or updated releases addressing this vulnerability. The GitHub Issue Discussion #3938 contains additional technical details and community discussion regarding remediation options. Consult the VulDB Vulnerability #359961 entry for ongoing tracking of patch availability.

Workarounds

• Generate and configure a unique, random token value of at least 32 characters to replace the default token
• Implement IP-based access controls to limit OpenAPI endpoint access to trusted administrative networks only
• Deploy a reverse proxy or web application firewall (WAF) in front of xxl-job to add an additional authentication layer
• Enable audit logging for all API operations to maintain visibility into endpoint usage

# Configuration example - Generate a secure random token and update configuration
# Generate a cryptographically secure random token
openssl rand -hex 32

# Update xxl-job configuration (application.properties or equivalent)
# Replace the default_token with your generated secure token
# xxl.job.accessToken=YOUR_GENERATED_SECURE_TOKEN_HERE

# Restrict access to OpenAPI endpoints via iptables (example)
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP