CVE-2026-50411 in Windows
Summary
by MITRE • 07/14/2026
Stack-based buffer overflow in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical stack-based buffer overflow within Active Directory Federation Services that enables remote attackers to execute denial of service attacks against targeted systems. The flaw occurs when AD FS processes malformed authentication requests or tokens, causing the application to write data beyond the bounds of allocated stack memory buffers. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, which is particularly dangerous because it can lead to arbitrary code execution or system instability when exploited properly.
The technical implementation of this vulnerability involves the improper handling of user-supplied input during federation authentication flows within the AD FS service. When malicious actors submit crafted requests containing oversized data payloads or malformed parameters, the service fails to validate buffer boundaries before copying data into fixed-size stack allocations. This allows attackers to overwrite adjacent memory locations including return addresses and control flow information, potentially enabling privilege escalation or complete system compromise.
From an operational impact perspective, this vulnerability creates significant security risks for organizations relying on AD FS for identity federation and single sign-on services. Attackers can leverage this flaw to disrupt authentication services, making it impossible for legitimate users to access federated applications and resources. The denial of service aspect specifically targets the availability of critical identity infrastructure components that many enterprise systems depend upon for secure access control and user authentication.
The attack vector for this vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks targeting services and infrastructure. Organizations running AD FS servers without proper patching become vulnerable to coordinated attacks that can render their identity federation capabilities completely non-functional, effectively cutting off access to numerous applications and services that depend on these authentication mechanisms.
Mitigation strategies should include immediate implementation of Microsoft security patches addressing the specific buffer overflow conditions within AD FS components. Network segmentation and monitoring of authentication traffic can help detect anomalous request patterns that may indicate exploitation attempts. Additionally, implementing proper input validation controls and boundary checking mechanisms within federation service configurations can reduce the attack surface. Organizations should also consider deploying intrusion detection systems specifically configured to monitor for known exploit signatures targeting AD FS vulnerabilities, while maintaining regular security assessments to identify and remediate similar weaknesses in federated identity infrastructure components.