CVE-2026-5709: AWS Research and Engineering Studio RCE

CVE-2026-5709 Overview

CVE-2026-5709 is a command injection vulnerability affecting AWS Research and Engineering Studio (RES) versions 2024.10 through 2025.12.01. The vulnerability exists due to unsanitized input in the FileBrowser API, which allows a remote authenticated attacker to execute arbitrary commands on the cluster-manager EC2 instance via crafted input when using the FileBrowser functionality.

This vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. Successfully exploiting this flaw could allow attackers to compromise the integrity and availability of the affected EC2 instance, potentially leading to full system compromise within the AWS environment.

Critical Impact

Authenticated attackers can execute arbitrary commands on the cluster-manager EC2 instance, potentially compromising the entire research environment and accessing sensitive data.

Affected Products

• AWS Research and Engineering Studio (RES) version 2024.10
• AWS Research and Engineering Studio (RES) versions through 2025.12.01

Discovery Timeline

• 2026-04-06 - CVE CVE-2026-5709 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5709

Vulnerability Analysis

The vulnerability resides in the FileBrowser API component of AWS Research and Engineering Studio. When authenticated users interact with the FileBrowser functionality, user-supplied input is passed to system commands without proper sanitization or validation. This allows specially crafted input to break out of the intended command context and inject additional OS commands.

The attack requires network access and valid authentication credentials, but once authenticated, an attacker with low privileges can exploit this vulnerability to execute arbitrary commands with the privileges of the cluster-manager process. This could result in unauthorized access to sensitive research data, lateral movement within the AWS environment, or complete compromise of the affected EC2 instance.

Root Cause

The root cause of CVE-2026-5709 is improper input validation in the FileBrowser API. User-controlled input is concatenated directly into OS commands without adequate sanitization, escaping, or parameterization. This allows attackers to inject shell metacharacters (such as ;, |, &&, or backticks) that break out of the intended command structure and execute additional arbitrary commands.

Attack Vector

The attack vector is network-based and requires authentication. An attacker must first obtain valid credentials to access the AWS Research and Engineering Studio environment. Once authenticated, the attacker can craft malicious input through the FileBrowser API endpoints.

The exploitation process involves submitting specially crafted file paths or parameters that contain command injection payloads. When the vulnerable API processes this input, the injected commands are executed on the underlying cluster-manager EC2 instance.

For technical details regarding this vulnerability, refer to the AWS Security Bulletin 2026-014 and the related GitHub Issue #150.

Detection Methods for CVE-2026-5709

Indicators of Compromise

• Unusual command execution patterns originating from the cluster-manager EC2 instance
• Unexpected process spawning from the RES FileBrowser service
• Anomalous network connections initiated by the cluster-manager process
• Evidence of shell metacharacters in FileBrowser API request logs

Detection Strategies

• Monitor AWS CloudTrail logs for suspicious API calls to the FileBrowser endpoints
• Implement Web Application Firewall (WAF) rules to detect command injection patterns in request parameters
• Enable detailed logging for the RES application and analyze for shell metacharacter sequences
• Deploy endpoint detection and response (EDR) solutions on cluster-manager instances to detect anomalous process execution

Monitoring Recommendations

• Configure CloudWatch alarms for unexpected command execution on cluster-manager instances
• Review VPC Flow Logs for unusual outbound connections from RES infrastructure
• Implement security groups and network ACLs to restrict unnecessary network access
• Enable AWS GuardDuty for enhanced threat detection across the RES environment

How to Mitigate CVE-2026-5709

Immediate Actions Required

• Upgrade AWS Research and Engineering Studio to version 2026.03 or later immediately
• Apply the corresponding mitigation patch to existing environments if immediate upgrade is not possible
• Review access logs for signs of exploitation attempts
• Restrict network access to the FileBrowser API to trusted IP ranges only

Patch Information

AWS has released version 2026.03 of Research and Engineering Studio to address this vulnerability. Users are strongly advised to upgrade to this version as soon as possible. The patched version includes proper input sanitization for the FileBrowser API, preventing command injection attacks.

For detailed upgrade instructions, refer to the GitHub Release 2026.03. Additional information is available in the AWS Security Bulletin 2026-014.

Workarounds

• Temporarily disable the FileBrowser functionality if not required for operations
• Implement network-level access controls to restrict FileBrowser API access to trusted users only
• Deploy a WAF with custom rules to filter requests containing shell metacharacters
• Enable multi-factor authentication for all RES users to reduce credential compromise risk

# Example: Restrict FileBrowser API access via security group
aws ec2 authorize-security-group-ingress \
  --group-id sg-xxxxxxxx \
  --protocol tcp \
  --port 443 \
  --cidr 10.0.0.0/8 \
  --description "Restrict RES access to internal network"