CVE-2026-54983 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
Active Directory Federation Services represents a critical component in enterprise identity management, serving as a federation server that authenticates users and provides single sign-on capabilities across distributed environments. This vulnerability manifests as a stack-based buffer overflow within the AD FS implementation that occurs when processing specially crafted authentication requests. The flaw exists in how the system handles incoming data structures during the federation process, particularly when parsing user credentials or token information. Attackers can exploit this weakness by sending malformed requests that exceed the allocated buffer space on the stack, potentially causing memory corruption and system instability.
The technical exploitation of this vulnerability follows established patterns for stack-based buffer overflow attacks where malicious input triggers a memory overwrite condition. When AD FS receives authentication requests containing oversized data payloads, the application fails to properly validate input lengths before copying data into fixed-size stack buffers. This allows attackers to overwrite adjacent memory locations including return addresses and control structures, which can lead to arbitrary code execution or denial of service conditions. The vulnerability affects the core authentication processing functionality and can be triggered through normal network communication channels without requiring elevated privileges.
The operational impact extends beyond simple denial of service scenarios as this weakness creates opportunities for more sophisticated attacks within enterprise environments. Organizations utilizing AD FS for identity federation face potential disruption to critical authentication services, affecting user access to applications and resources across the network infrastructure. The attack surface includes any system that relies on AD FS for authentication, making it particularly dangerous in large enterprise deployments where multiple services depend on the federation server. Network-based attacks can originate from external sources, potentially compromising the availability of authentication services for legitimate users.
Mitigation strategies should address both immediate protection and long-term security improvements within the AD FS infrastructure. Organizations must apply vendor-provided patches and updates as soon as they become available to address the buffer overflow condition directly. Network segmentation and access controls should be implemented to limit exposure of AD FS components to untrusted networks, reducing potential attack vectors. Monitoring systems should be enhanced to detect unusual authentication request patterns that might indicate exploitation attempts. Additionally, implementing proper input validation and bounds checking mechanisms within application code helps prevent similar vulnerabilities from occurring in future deployments. This vulnerability aligns with CWE-121 stack-based buffer overflow classifications and represents a significant concern for attackers following ATT&CK techniques related to privilege escalation and denial of service operations.