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AWS Bedrock AgentCore Python SDK Arbitrary Command Execution Vulnerability

An improper neutralization of argument delimiters vulnerability (CVE-2026-16796) in the AWS Bedrock AgentCore Python SDK's `install_packages()` method allows a remote authenticated user to execute arbitrary commands within the Code Interpreter sandbox by crafting malicious package name arguments.

The AWS Bedrock AgentCore Python SDK, specifically versions prior to 1.18.1, contains a critical vulnerability (CVE-2026-16796) related to improper input validation in its install_packages() method. This method, part of the Code Interpreter client designed to install Python packages into a managed sandbox, can be exploited by a remote authenticated user. By crafting malicious package name arguments that include argument delimiters, an attacker can bypass the SDK's validation mechanisms. This leads to arbitrary command execution within the isolated Code Interpreter sandbox environment. The vulnerability impacts organizations using bedrock-agentcore versions before 1.18.1, potentially allowing unauthorized code execution in their AI agent development and deployment environments. AWS released a patch in version 1.18.1 to address this issue.

Attack Chain

  1. An authenticated attacker identifies an opportunity to influence the arguments passed to the install_packages() method of the AWS Bedrock AgentCore Python SDK. This might occur in an application that accepts dynamic or user-supplied package names for installation.
  2. The attacker crafts a malicious package specifier (e.g., a package name or an extras group) that includes argument delimiters or shell metacharacters, such as semicolons, pipes, or command substitutions.
  3. The bedrock-agentcore SDK, specifically the install_packages() method in affected versions, improperly neutralizes these delimiters during input validation.
  4. The Code Interpreter sandbox environment, where the packages are intended to be installed, processes the malformed package specifier.
  5. Due to the unneutralized delimiters, the underlying system command or shell interpreter within the sandbox executes the attacker-supplied arbitrary commands.
  6. The attacker achieves arbitrary command execution within the managed Code Interpreter sandbox, potentially leading to data manipulation, unauthorized access, or further compromise of the sandboxed environment.

Impact

The improper neutralization of argument delimiters in the install_packages() method of the AWS Bedrock AgentCore Python SDK (CVE-2026-16796) allows remote authenticated users to bypass input validation and execute arbitrary commands within the Code Interpreter sandbox. If exploited, this vulnerability grants an attacker unauthorized control over the sandboxed environment, potentially enabling data exfiltration, service disruption, or further lateral movement within an affected system. The specific number of affected organizations is not provided, but any AWS Bedrock AgentCore deployments using bedrock-agentcore versions prior to 1.18.1 are at risk, particularly those that process untrusted or model-generated inputs for package installations.

Recommendation

  • Immediately upgrade all instances of the bedrock-agentcore Python SDK to version 1.18.1 or later to remediate CVE-2026-16796.
  • Ensure that any custom or forked code derived from bedrock-agentcore is patched to incorporate the fixes from version 1.18.1.
  • Implement strict input validation for any dynamic package names supplied to install_packages(), adhering to PyPI naming rules and constraining extras groups to comma-separated identifiers, as a workaround if immediate upgrade is not possible.
  • Avoid passing untrusted or model-generated input directly to the install_packages() method.