CVE-2026-85012 in blueprints
Summary
by MITRE • 09/03/2026
Improper neutralization of special elements used in an OS command (CWE-78) in the blueprint resynthesis framework in Amazon Web Services codecatalyst-blueprints before 0.3.156 might allow a user with permission to commit to a repository in the project to execute arbitrary commands in the blueprint resynthesis environment via shell metacharacters in the owner field of a [local] merge strategy entry in a crafted .ownership-file.
Version 0.3.156 removes shell interpretation of the owner field, running the command directly rather than through a shell, and rejects values outside an allowlisted command form. This eliminates shell metacharacter command injection. To remediate this issue, users should upgrade to version 0.3.156 or later.
No action is required for use of the Amazon CodeCatalyst service. Resynthesis runs in an isolated per-project environment with scoped credentials, and the service applies server-side validation there that rejects [local] merge strategy commands outside a restricted allowlisted form, including for blueprint versions published before 0.3.156.
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Analysis
by VulDB Data Team • 09/03/2026
The vulnerability identified as CWE-78 represents an improper neutralization of special elements used in OS command injection within the blueprint resynthesis framework of Amazon Web Services CodeCatalyst prior to version 0.3.156. This flaw specifically affects the handling of the owner field within a local merge strategy entry found in crafted .ownership-files. The core technical deficiency lies in the application's failure to properly sanitize user-supplied input before incorporating it into operating system commands. By allowing shell metacharacters to pass through without adequate filtering or escaping, the software inadvertently enables an attacker who possesses commit permissions for a repository within the project to inject arbitrary commands. These commands are executed within the blueprint resynthesis environment, which is designed to process and apply changes based on configuration files such as .ownership-files. The presence of shell metacharacters allows for command chaining or substitution, thereby bypassing intended logical constraints and leading to unauthorized code execution.
From an operational perspective, this vulnerability poses a significant risk if the affected component were exposed in a manner that allowed untrusted input to trigger the resynthesis process without sufficient isolation. An attacker could leverage this flaw to execute arbitrary system commands, potentially gaining access to sensitive data, modifying project configurations, or using the compromised environment as a pivot point for further attacks against other systems within the network infrastructure. The impact is directly tied to the privileges of the user account under which the resynthesis process runs and the accessibility of the repository containing the crafted .ownership-file. While the vulnerability allows for command injection, its practical exploitation depends on the attacker's ability to commit malicious files to a target project where the vulnerable version of the blueprint resynthesis framework is active.
In terms of industry standards mapping, this issue aligns with CWE-78: Improper Neutralization of Special Elements used in an OS Command (OS Command Injection). Furthermore, from a tactical perspective relevant to threat modeling and detection engineering, this vulnerability corresponds to ATT&CK technique T1059.004: Command and Scripting Interpreter::Unix Shell Commands. This classification highlights the mechanism by which attackers utilize shell interpreters to execute malicious payloads after gaining initial access through input manipulation. Understanding these mappings is crucial for security teams aiming to detect similar injection patterns in other applications or to configure intrusion detection systems that monitor for suspicious command execution sequences originating from web application inputs.
The remediation strategy involves upgrading the blueprint resynthesis framework to version 0.3.156 or later. This update addresses the root cause by removing shell interpretation of the owner field, thereby ensuring that commands are executed directly rather than through a shell interpreter. Additionally, the updated implementation rejects any values that do not conform to an allowlisted command form, effectively neutralizing the possibility of injecting arbitrary shell metacharacters. For organizations utilizing the Amazon CodeCatalyst service, no immediate action is required regarding this specific vulnerability because the resynthesis process runs in an isolated per-project environment with scoped credentials. The service applies server-side validation that rejects local merge strategy commands outside a restricted allowlisted form, even for blueprint versions published before 0.3.156. This server-side control acts as a critical defense-in-depth measure, ensuring that client-side vulnerabilities do not translate into successful exploitation within the managed cloud environment.