CVE-2026-85337 in Windows
Summary
by MITRE • 10/14/2026
Out-of-bounds read in Remote Desktop Client allows an unauthorized attacker to disclose information over a network.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified as an out-of-bounds read within the Microsoft Remote Desktop Client represents a critical memory safety flaw that enables remote attackers to extract sensitive data from the victim's system without requiring authentication or prior access privileges. This specific type of error occurs when the application attempts to read data from a memory location that lies outside the intended buffer boundaries, typically due to insufficient validation of input parameters such as packet lengths or array indices during the processing of Remote Desktop Protocol traffic. In many implementations involving network-facing services like RDP clients, malformed packets crafted by an attacker can trigger this condition, causing the application to access adjacent memory regions containing stack variables, heap metadata, or other sensitive information that was not intended for disclosure.
From a technical perspective, out-of-bounds reads are particularly dangerous because they often lead to information leakage rather than immediate code execution, although they can serve as precursors to more severe exploits if combined with other vulnerabilities. The attacker leverages the network interface of the Remote Desktop Client to send specially constructed requests that exploit logic errors in how data structures are parsed and validated. When the client processes these malicious inputs, it fails to verify whether the requested read operation stays within the allocated memory limits. Consequently, the application returns or exposes contents from neighboring memory addresses, which may include cryptographic keys, session tokens, user credentials, or internal state information that can be used for further attacks against the target infrastructure.
The operational impact of this vulnerability is significant due to its remote nature and lack of authentication requirements. An attacker positioned on the same network segment or with access to the internet-facing interface of a system running the vulnerable client version can initiate an attack from any location without needing valid user credentials. This capability allows for stealthy reconnaissance activities where the adversary gathers intelligence about the target environment, potentially leading to privilege escalation, session hijacking, or lateral movement within a corporate network. The ability to disclose information remotely undermines the confidentiality guarantees provided by secure communication protocols and exposes organizations to data breaches that may violate regulatory compliance standards such as GDPR, HIPAA, or PCI-DSS depending on the nature of the leaked data.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-125, which describes out-of-bounds read errors resulting from improper validation of array indices or buffer sizes. In terms of offensive security frameworks, this exploit technique corresponds to ATT&CK tactic T1046, Network Service Discovery, specifically under the subtechnique for exploiting vulnerabilities in network services to gather information about connected systems and their configurations. The exploitation vector is classified as Remote (Network) with Low Complexity, indicating that while specialized tools may be required to craft the malicious packets, the attack does not require complex conditions or user interaction beyond having network connectivity to the target service.
Mitigation strategies must prioritize immediate patching of all affected versions of the Microsoft Remote Desktop Client using official security updates provided by the vendor. Organizations should verify their inventory for systems running vulnerable client builds and apply patches as soon as they become available through trusted channels such as Windows Update or WSUS. In environments where patching cannot be implemented immediately, network-level controls should be deployed to restrict access to RDP services from untrusted networks. This includes configuring firewalls to allow connections only from known IP addresses, implementing strict ingress filtering rules, and disabling unnecessary remote desktop functionalities if they are not required for business operations. Additionally, deploying intrusion detection systems with signatures capable of identifying malformed RDP packets can provide an additional layer of defense by blocking exploit attempts before they reach the vulnerable application logic.