Microsoft IIS Vulnerability Allows Unauthorized Attacker To execute Malicious Code

Microsoft has identified a critical vulnerability, CVE-2025-59282, in its Internet Information Services (IIS) platform. This flaw, which affects Windows servers used for web hosting, arises due to a race condition and use-after-free error within the Inbox COM Objects handling global memory.

Announced on October 14, 2025, the vulnerability has been assigned a CVSS 3.1 base score of 7.0 and is marked as "Important." While there are no reports of active exploitation, the vulnerability permits arbitrary code execution, potentially compromising server integrity and facilitating broader network attacks.

The issue manifests during concurrent execution where improper synchronization of shared resources allows unauthorized manipulation of memory states. Exploitation requires local access, but this can be leveraged by a remote attacker through phishing tactics to trick users into opening malicious files.

Although no elevated privileges are necessary, the complexity of the attack involves precise timing to exploit the race condition. Successful exploitation could result in arbitrary code execution with the privileges of the IIS process, which could be SYSTEM on misconfigured servers.

This vulnerability is particularly concerning in enterprise environments, where it could expose sensitive applications and data to threats like ransomware or data exfiltration. Despite the "Exploitation Unlikely" rating from Microsoft's MSRC, the absence of patches necessitates immediate updates.

Currently, there are no indicators of compromise (IoCs) available, but monitoring for unusual COM object interactions or memory anomalies is recommended.

To mitigate risks, it is advised to disable IIS if it is not in use. Microsoft recommends applying future patches via Windows Update and implementing restrictive file execution policies. Enabling User Account Control (UAC) and auditing COM interactions can further enhance security.

Security researchers, including Zhiniang Peng from HUST and R4nger from CyberKunLun, stress the importance of timely patching to prevent escalation. With IIS serving as the backbone for numerous web servers, this vulnerability highlights the necessity for rigorous memory-safe coding practices in legacy components. Organizations are urged to scan their environments and review web server configurations promptly.

Based on reporting by Cyber Security News.