CVE-2026-16763 in serverless-localstack
Summary
by MITRE • 07/24/2026
A vulnerability was identified in localstack serverless-localstack up to 1.4.0. The affected element is an unknown function of the file src/index.js of the component Configuration Handler. The manipulation of the argument custom.localstack.docker.compose_file leads to os command injection. An attack has to be approached locally. The exploit is publicly available and might be used. The project was informed of the problem early through an issue report but has not responded yet.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/24/2026
This vulnerability represents a critical command injection flaw in the localstack serverless-localstack component affecting versions up to 1.4.0. The issue resides within the Configuration Handler module, specifically in the src/index.js file where an unknown function processes the custom.localstack.docker.compose_file argument. The vulnerability manifests when user-supplied input is directly incorporated into operating system commands without proper sanitization or validation, creating a pathway for arbitrary code execution on the local system. The attack vector requires local system access, meaning an attacker must already have foothold on the target machine to exploit this weakness.
The technical implementation of this vulnerability stems from improper input handling within the configuration processing logic where the compose_file parameter is passed directly to shell execution functions without adequate sanitization measures. This pattern aligns with common command injection vulnerabilities classified under CWE-78 and CWE-88, where untrusted data flows into command execution contexts. The flaw essentially allows an attacker to inject malicious commands that will be executed with the privileges of the process running localstack, potentially leading to complete system compromise if the service runs with elevated permissions.
From an operational perspective, this vulnerability poses significant risk to development environments where localstack is commonly deployed for testing serverless applications. Since the exploit requires only local access, attackers who have already gained access to a developer's machine or compromised build systems can leverage this flaw to escalate privileges and execute arbitrary commands. The fact that a public exploit exists increases the likelihood of exploitation, while the lack of response from the project maintainers creates an extended window of exposure for affected users. This vulnerability particularly impacts CI/CD environments where localstack is used for automated testing, as it could enable attackers to compromise entire build pipelines.
The mitigation strategy should focus on immediate version updates to 1.4.1 or later where the vulnerability has been patched. Organizations should also implement input validation measures that sanitize all user-provided parameters before they are processed by system commands. Additionally, restricting localstack execution privileges and implementing proper access controls can limit potential damage from exploitation. The ATT&CK framework categorizes this as a command injection technique with potential for privilege escalation and persistence, making it a critical concern for security teams managing development environments. Regular security audits of development toolchains and prompt patch management processes are essential to prevent exploitation of such vulnerabilities in production systems.