CVE-2026-3519 Overview
CVE-2026-3519 is an OS Command Injection vulnerability affecting Progress ADC Products, specifically the LoadMaster appliance. This vulnerability allows an authenticated attacker with "VS Administration" permissions to execute arbitrary commands on the LoadMaster appliance by exploiting unsanitized input in the aclcontrol command within the API.
Critical Impact
Authenticated attackers with administrative privileges can achieve full remote code execution on LoadMaster appliances, potentially compromising network traffic management and load balancing infrastructure.
Affected Products
- Progress LoadMaster appliances
- Progress ADC Products with vulnerable API implementations
Discovery Timeline
- 2026-04-20 - CVE-2026-3519 published to NVD
- 2026-04-20 - Last updated in NVD database
Technical Details for CVE-2026-3519
Vulnerability Analysis
This command injection vulnerability (CWE-77: Improper Neutralization of Special Elements used in a Command) exists within the API layer of Progress LoadMaster appliances. The vulnerability stems from insufficient input sanitization in the aclcontrol command handler, allowing specially crafted input to break out of the intended command context and execute arbitrary system commands.
The attack requires adjacent network access and high privileges ("VS Administration" permissions), but the scope is changed, meaning a successful exploit can impact resources beyond the vulnerable component's security scope. This allows attackers to potentially pivot to other systems or access sensitive data managed by the load balancer.
Root Cause
The root cause is improper neutralization of special elements in the aclcontrol command parameter processing. User-supplied input is passed directly to system command execution without adequate sanitization or validation, allowing command separator characters and shell metacharacters to inject additional commands.
Attack Vector
The attack requires adjacent network access to the LoadMaster management interface. An attacker must first authenticate with "VS Administration" permissions, then submit malicious input through the API's aclcontrol functionality. The unsanitized input allows injection of arbitrary OS commands that execute with the privileges of the LoadMaster service process.
The vulnerability manifests in the API's handling of ACL control operations. Attackers can append command separators (such as semicolons or backticks) followed by malicious commands to the expected input parameters. For detailed technical information, see the Progress LoadMaster Security Advisory.
Detection Methods for CVE-2026-3519
Indicators of Compromise
- Unusual API requests to the aclcontrol endpoint containing shell metacharacters or command separators
- Unexpected process spawning from LoadMaster service processes
- Anomalous network connections originating from the LoadMaster appliance
- Suspicious entries in LoadMaster logs indicating command injection attempts
Detection Strategies
- Monitor API access logs for requests containing command injection patterns such as semicolons, backticks, pipe characters, or $(...) constructs
- Implement network-based detection rules for command injection payloads targeting LoadMaster management interfaces
- Deploy endpoint detection on management systems that access LoadMaster appliances to identify compromised administrator accounts
- Review authentication logs for unusual "VS Administration" account activity
Monitoring Recommendations
- Enable verbose logging on LoadMaster API endpoints and forward logs to a SIEM for analysis
- Configure alerts for any command execution anomalies on LoadMaster appliances
- Monitor for lateral movement attempts originating from LoadMaster network segments
How to Mitigate CVE-2026-3519
Immediate Actions Required
- Apply the security patch from Progress Software immediately
- Review and audit all accounts with "VS Administration" permissions
- Restrict network access to the LoadMaster management interface to trusted administrator workstations only
- Enable additional logging and monitoring on LoadMaster appliances pending patch deployment
Patch Information
Progress Software has released security updates addressing CVE-2026-3519. Organizations should review the Progress LoadMaster Security Advisory for specific patch versions and upgrade instructions applicable to their deployment.
Workarounds
- Implement network segmentation to restrict access to LoadMaster management interfaces from adjacent network segments
- Apply the principle of least privilege by reviewing and reducing the number of accounts with "VS Administration" permissions
- Deploy web application firewall (WAF) rules to filter command injection patterns in API requests to LoadMaster management endpoints
Configuration hardening example - restrict management interface access:
# Example: Restrict management access to specific administrator networks
# Apply these configurations according to your LoadMaster deployment
# Consult Progress documentation for exact syntax
# Limit management interface access to trusted IP ranges
# Review all "VS Administration" accounts and remove unnecessary privileges
# Enable audit logging for all API operations
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
