CVE-2025-50460 is a remote code execution (RCE) vulnerability identified in the ms-swift project version 3.3.0. The root cause lies in unsafe deserialization practices within the tests/run.py script, which uses the PyYAML library version 5.3.1's yaml.load() function to parse YAML configuration files. This function is inherently unsafe when processing untrusted input because it can instantiate arbitrary Python objects during deserialization. An attacker who can control the YAML configuration file passed to the --run_config parameter can craft malicious YAML content that executes arbitrary Python code, such as invoking os.system() commands. This leads to the possibility of full system compromise on the affected host. The vulnerability is triggered at runtime when the malicious YAML file is loaded, allowing execution of arbitrary commands with the privileges of the running process. The recommended mitigation is to upgrade PyYAML to version 5.4 or higher, which includes safer defaults, and to replace yaml.load() with yaml.safe_load(), which restricts deserialization to simple Python objects and prevents arbitrary code execution. No known exploits are currently reported in the wild, but the vulnerability presents a critical risk due to the ease of exploitation if an attacker can supply or influence the YAML configuration input. The vulnerability was published on August 1, 2025, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a significant risk especially for those using the ms-swift project or similar Python-based applications that rely on PyYAML for configuration management. Successful exploitation can lead to full system compromise, allowing attackers to execute arbitrary commands, potentially leading to data theft, service disruption, lateral movement within networks, or deployment of ransomware. Organizations in sectors with high reliance on automation, continuous integration/continuous deployment (CI/CD) pipelines, or infrastructure-as-code that utilize YAML configurations are particularly vulnerable. The impact extends to confidentiality, integrity, and availability of systems. Given the ability to execute arbitrary code remotely, attackers could gain persistent access or disrupt critical services. European entities handling sensitive data or critical infrastructure could face regulatory consequences under GDPR if breaches occur due to this vulnerability.

To mitigate this vulnerability, European organizations should: 1) Immediately audit all uses of PyYAML in their codebases, especially scripts or applications that load YAML files from untrusted sources. 2) Upgrade PyYAML to version 5.4 or later, which addresses unsafe deserialization issues. 3) Replace all instances of yaml.load() with yaml.safe_load() to restrict deserialization to safe Python objects. 4) Implement strict input validation and integrity checks on YAML configuration files, ensuring only trusted and verified files are processed. 5) Restrict access to configuration files and the execution environment to minimize the risk of malicious file injection. 6) Monitor logs and system behavior for unusual activity indicative of exploitation attempts. 7) Incorporate security testing focused on deserialization vulnerabilities in development and deployment pipelines. 8) Educate developers and DevOps teams about the risks of unsafe deserialization and secure coding practices related to YAML processing.