CVE-2026-97830 in Windows
Summary
by MITRE • 10/14/2026
Double free in Windows Internet Information Services allows an unauthorized attacker to deny service over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves a critical memory management error within the Microsoft Windows Internet Information Services, specifically classified as a double free condition. This type of flaw occurs when a program attempts to deallocate or release a block of memory that has already been freed by an earlier operation in the same execution context. In the specific case of IIS, this defect resides deep within the service's handling of network requests, allowing an attacker who can send specially crafted data over the network to trigger this erroneous sequence. The presence of such a flaw indicates a failure in the application logic to properly track memory allocation states or validate pointers before performing deallocation operations, which is a fundamental requirement for stable software operation.
From a technical perspective, double free vulnerabilities are particularly dangerous because they corrupt the heap metadata used by the operating system's memory manager. When an attacker triggers this condition, the integrity of the underlying data structures that manage dynamic memory allocation is compromised. This corruption can lead to unpredictable behavior within the IIS process, ranging from minor glitches to a complete crash of the service worker process responsible for handling web requests. The exploitability of this flaw relies on the ability to control or influence the state of the heap in a way that forces the application into an invalid memory release sequence, often by sending malformed HTTP headers or request bodies that bypass standard input validation checks.
The operational impact of this vulnerability is primarily centered around availability and service disruption. Since IIS serves as the web server infrastructure for numerous enterprise applications, its compromise can lead to significant downtime. An unauthorized attacker does not necessarily need authentication to exploit this flaw; a simple network connection with maliciously crafted packets is sufficient to trigger the double free condition. This results in a denial of service scenario where legitimate users are unable to access hosted websites or web services because the IIS process has crashed or become unresponsive due to memory corruption. In some advanced exploitation scenarios, heap corruption could potentially be leveraged for further attacks, such as arbitrary code execution, although the primary reported impact remains the disruption of service availability.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifier CWE-415, which defines Double Free vulnerabilities. It also maps to MITRE ATT&CK techniques related to resource exhaustion and denial of service, specifically falling under tactics that aim to degrade or destroy system functionality without necessarily gaining persistent access. The lack of authentication requirements places it in the category of network-based attacks that can be executed remotely by unauthenticated adversaries, increasing its severity rating significantly within enterprise security assessments.
To mitigate this risk, organizations must ensure that all Windows systems running Internet Information Services are updated with the latest cumulative updates and security patches provided by Microsoft. These patches typically include fixes for memory management logic errors like double free conditions. Administrators should verify patch compliance across all web server nodes in their infrastructure. Additionally, implementing network-level protections such as Web Application Firewalls can help detect and block malformed requests that attempt to exploit heap corruption vulnerabilities before they reach the IIS application layer. Regular vulnerability scanning focused on outdated software versions is also recommended to identify systems still exposed to this flaw until patches are fully deployed.