Microsoft has recently disclosed a significant security flaw within its Internet Information Services (IIS) platform, identified as CVE-2025-59282. This vulnerability poses a substantial risk to organizations utilizing Windows servers for web hosting, as it could potentially allow unauthorized attackers to execute malicious code remotely.
Understanding CVE-2025-59282
CVE-2025-59282 is a critical remote code execution vulnerability stemming from a race condition and use-after-free error in the handling of global memory by IIS’s Inbox COM Objects. Announced on October 14, 2025, this flaw has been assigned a CVSS 3.1 base score of 7.0 and is rated as Important by Microsoft. Although there have been no reports of this vulnerability being exploited in the wild, security experts caution that its potential for arbitrary code execution could enable attackers to compromise server integrity, steal sensitive data, or launch broader network attacks.
Technical Details
The vulnerability arises during concurrent execution when shared resources lack proper synchronization, allowing an unauthorized attacker to manipulate memory states. Exploitation requires local access, which can be achieved by a remote adversary tricking a user into opening a malicious file. No special privileges are needed; however, the high attack complexity demands precise timing to exploit the race condition, making it challenging yet feasible for skilled threat actors.
At its core, CVE-2025-59282 exploits weaknesses in CWE-362 (race condition) and CWE-416 (use-after-free) within IIS’s COM object management. When a user interacts with a crafted file, such as a specially malformed document or script, the vulnerability triggers improper memory handling, leading to a use-after-free scenario where freed memory is accessed concurrently, enabling code injection.
The CVSS vector string, CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H, highlights key factors: local attack vector, high complexity, required user interaction, and high impacts across confidentiality, integrity, and availability. Microsoft clarifies that remote in the title refers to the attacker’s position, not the execution site, distinguishing it from fully remote exploits.
Potential Impact
Successful exploitation of this vulnerability could allow attackers to run arbitrary code with the privileges of the IIS process, which often runs as SYSTEM on misconfigured servers. In enterprise environments, this might expose sensitive web applications, databases, or API endpoints to ransomware deployment, data exfiltration, or lateral movement. For instance, a compromised IIS server in a corporate intranet could serve as an entry point for advanced persistent threats targeting financial or healthcare sectors.
Given the Exploitation Unlikely assessment from Microsoft’s Security Response Center (MSRC), immediate threats remain low. However, the lack of patches at disclosure time urges urgent updates. No indicators of compromise (IoCs) have been detailed yet, but monitoring for unusual COM object interactions or memory anomalies in IIS logs is advised.
Mitigation Strategies
To mitigate the risks associated with CVE-2025-59282, organizations should consider the following steps:
1. Disable IIS if Unused: If IIS is not actively used, disabling it can eliminate the risk associated with this vulnerability.
2. Apply Patches Promptly: Microsoft recommends applying forthcoming patches via Windows Update as soon as they become available.
3. Restrict File Execution Policies: Implementing strict file execution policies can prevent unauthorized code execution.
4. Enable User Account Control (UAC): Activating UAC can help prevent unauthorized changes to the system.
5. Audit COM Interactions: Regularly auditing COM interactions can help detect and prevent exploitation attempts.
Security researchers, including Zhiniang Peng from HUST and R4nger from CyberKunLun, emphasize the importance of timely patching to prevent potential escalation. As IIS powers millions of web servers, this vulnerability underscores the need for vigilant memory-safe coding in legacy components. Organizations should scan their environments and review web server configurations promptly to ensure they are not susceptible to this flaw.
Broader Context
This disclosure is part of a series of vulnerabilities affecting Microsoft’s IIS platform. For instance, a critical vulnerability in the Microsoft Web Deploy tool, tracked as CVE-2025-53772, was disclosed on August 12, 2025. This flaw allows authenticated attackers to execute remote code on affected systems and carries a CVSS score of 8.8, indicating high severity. The vulnerability stems from the deserialization of untrusted data in Web Deploy, classified under the CWE-502 weakness category. This vulnerability affects Web Deploy 4.0 and requires low privileges to exploit, making it particularly concerning for organizations using this deployment tool in their infrastructure.
Additionally, a proof-of-concept exploit for CVE-2025-53772 was published on September 25, 2025, raising urgent alarms across the .NET and DevOps communities. The flaw resides in the unsafe deserialization of HTTP header contents in both the msdeployagentservice and msdeploy.axd endpoints, enabling authenticated attackers to execute arbitrary code on target servers. The proof-of-concept uses the MSDeploy.SyncOptions header to spawn commands, highlighting the ease with which this vulnerability can be exploited.
Furthermore, a sophisticated cyber campaign, dubbed Operation Rewrite, has been actively hijacking Microsoft IIS web servers to serve malicious content through a technique known as search engine optimization (SEO) poisoning. Palo Alto Networks uncovered the operation in March 2025, attributing it with high confidence to a Chinese-speaking threat actor who uses a malicious IIS module known as BadIIS. The campaign’s primary goal is financial gain by manipulating search engine results to redirect unsuspecting users to unwanted websites, such as gambling and pornography platforms. The attackers compromise legitimate, high-reputation websites, turning them into unwitting conduits for their malicious activities.
Conclusion
The disclosure of CVE-2025-59282 highlights the ongoing challenges in securing web server platforms like Microsoft IIS. Organizations must remain vigilant, promptly apply security patches, and implement robust monitoring to detect and mitigate potential exploitation attempts. By taking proactive measures, organizations can protect their systems and data from emerging threats targeting web server vulnerabilities.
