CVE-2025-54364 is a vulnerability classified under CWE-1333, indicating inefficient regular expression complexity leading to a potential Regular Expression Denial of Service (ReDoS) attack. This vulnerability affects Microsoft Knack version 0.12.0, specifically within the knack.introspection module. The root cause is an inefficient regular expression pattern used in the option_descriptions function: "\s(:param)\s+(.+?)\s:(.*)". This pattern is vulnerable to catastrophic backtracking when processing specially crafted docstrings that contain a large volume of whitespace without a terminating colon. An attacker capable of injecting or controlling docstring content in applications using this module can exploit this flaw to cause excessive CPU consumption, effectively leading to a denial of service by exhausting system resources. Microsoft Knack is utilized by Azure CLI, which is widely used for managing Azure cloud resources. The vulnerability has a CVSS 4.0 base score of 6.9, indicating a medium severity level. The attack vector is local (AV:L), requiring the attacker to have local access or the ability to influence local input, with no privileges or user interaction needed. The vulnerability does not affect confidentiality, integrity, or availability directly but impacts availability through resource exhaustion. No known exploits are reported in the wild as of the publication date (August 20, 2025), and no patches have been linked yet. The vulnerability is significant because it can degrade or disrupt cloud management operations that rely on Azure CLI, potentially impacting automation, deployment, and management workflows in cloud environments.

For European organizations, the impact of CVE-2025-54364 can be substantial, particularly for enterprises and service providers heavily reliant on Azure cloud services and automation via Azure CLI. A successful ReDoS attack could lead to denial of service conditions on systems running affected versions of Microsoft Knack, causing delays or failures in cloud resource management tasks. This can disrupt business-critical operations, including deployment pipelines, monitoring, and scaling of cloud infrastructure. The CPU exhaustion caused by the vulnerability could also increase operational costs due to resource overutilization and may trigger cascading failures in dependent systems. Additionally, organizations subject to strict service level agreements (SLAs) or regulatory requirements around availability and uptime could face compliance risks. While the attack requires local access or the ability to inject docstring content, insider threats or compromised development environments could be vectors. The vulnerability's presence in Azure CLI, a widely used tool, increases the attack surface across various sectors including finance, healthcare, manufacturing, and government institutions in Europe that leverage Azure cloud services.

To mitigate this vulnerability, European organizations should: 1) Immediately audit their environments to identify usage of Microsoft Knack version 0.12.0, especially within Azure CLI installations. 2) Monitor official Microsoft and Azure CLI channels for patches or updates addressing CVE-2025-54364 and apply them promptly once available. 3) Implement input validation and sanitization controls to prevent injection or manipulation of docstring content that could trigger the vulnerable regex pattern. 4) Restrict local access and enforce strict access controls to limit the ability of attackers to inject malicious docstrings, including hardening development and deployment environments. 5) Employ resource monitoring and alerting to detect unusual CPU usage patterns indicative of ReDoS attempts. 6) Consider isolating or sandboxing components that process docstrings to contain potential resource exhaustion impacts. 7) Educate developers and DevOps teams about the risks of inefficient regex patterns and encourage secure coding practices to avoid similar vulnerabilities in custom code.