Windows PowerShell 0-Day Lets Attackers Execute Arbitrary Code

Microsoft has disclosed a critical remote code execution vulnerability in Windows PowerShell that could allow attackers to execute arbitrary code on vulnerable systems.

The flaw, tracked as CVE-2025-54100, was publicly disclosed on December 9, 2025, and poses a significant security risk to organizations worldwide.

The vulnerability arises from improper neutralisation of special elements used in command execution, allowing attackers to inject malicious commands via PowerShell.

An attacker with local access and user interaction could exploit this flaw to gain elevated privileges and execute arbitrary code on the target system.

The remote code execution flaw affects PowerShell’s command processing mechanism. Microsoft classified the vulnerability as “Important” severity, indicating it requires prompt patching.

The attack requires local access and user interaction, meaning a victim must be tricked into executing a malicious PowerShell command or script.

Organizations that use PowerShell for system administration, automation, or scripting face an elevated risk.

Field	Value
CVE ID	CVE-2025-54100
Vulnerability Type	Remote Code Execution
Severity	Important
Max CVSS Score	7.8

The vulnerability could be chained with other exploits to escalate attacks or compromise sensitive data. Microsoft has not yet released official patch information, but users are urged to monitor security bulletins closely.

While the vulnerability requires local access and user interaction, it can be leveraged by malware authors and threat actors to escape sandboxes or gain code execution during targeted campaigns.

The flaw could be exploited through phishing emails with malicious attachments, watering-hole attacks, or supply-chain compromises.

Security teams should implement defensive measures immediately, including restricting PowerShell execution policies, turning off unnecessary scripts, and monitoring command-line activity for suspicious behavior.

Enterprises should consider deploying detection rules specifically targeting PowerShell injection attempts.

Microsoft recommends applying security patches immediately upon release. Until patches are available, organizations should apply the principle of least privilege to PowerShell execution and monitor all PowerShell activities for indicators of compromise.

Threat intelligence teams should prepare incident response procedures and monitor dark web forums for exploit code or proof-of-concept releases.

Network defenders should implement additional monitoring for PowerShell-related anomalies and suspicious command execution patterns.

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