CVE-2026-102870 in ASP.NET Core
Summary
by MITRE • 10/13/2026
Improper control of generation of code ('code injection') in ASP.NET Core allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the ASP.NET Core framework, specifically categorized under improper control of code generation which leads directly to code injection capabilities. This type of defect typically arises when the application or its underlying runtime fails to adequately sanitize inputs that are subsequently processed as executable logic or script content. In the context of web applications built on ASP.NET Core, this often manifests through dynamic compilation features such as Razor Pages views, custom tag helpers, or any mechanism where user-supplied data is interpolated into code strings without rigorous validation. When an attacker provides maliciously crafted input that bypasses existing filtering mechanisms, they can inject arbitrary commands or scripts that the server executes with the privileges of the application pool identity. This represents a severe breach of integrity and confidentiality, as it allows for remote code execution (RCE) over a network connection, effectively granting the adversary full control over the affected system depending on the configuration and permissions assigned to the web service process.
From an operational perspective, the impact of this vulnerability is profound and multifaceted. An unauthorized attacker who exploits this flaw can achieve complete compromise of the host environment. This may involve reading sensitive data stored in memory or on disk, modifying application logic to create backdoors, pivoting to other systems within the internal network, or deploying ransomware and cryptominers. The ability to execute code remotely means that traditional perimeter defenses such as firewalls are insufficient if the vulnerability is exposed via HTTP endpoints. Attackers can leverage this access to exfiltrate customer data, disrupt business operations by taking services offline, or use the compromised server as a launchpad for further attacks against downstream infrastructure. The severity is amplified in cloud-native environments where containerized applications might share host resources, potentially leading to broader system compromise beyond the immediate application scope.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) identifiers such as CWE-94 Improper Control of Generation of Code ('Code Injection') and often overlaps with CWE-78 OS Command Injection if shell commands are executed directly. In terms of offensive security frameworks, this exploit scenario maps to the MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically regarding remote execution capabilities. It also relates to initial access vectors like T1190 Exploit Public-Facing Application, highlighting the risk posed by internet-facing services that utilize vulnerable versions of ASP.NET Core without proper patching or input validation layers. Understanding these mappings is crucial for security teams to prioritize remediation efforts and align them with industry-standard threat models.
Mitigation strategies must focus on both immediate technical fixes and long-term architectural improvements. The primary remedy involves upgrading the ASP.NET Core framework to a version where this specific code generation flaw has been patched by Microsoft, ensuring that all dependencies are updated accordingly. Developers should rigorously audit any areas of the application that dynamically generate or compile code based on user input, replacing unsafe practices with safer alternatives such as pre-compiled views or parameterized queries for data access rather than logic injection. Implementing strict input validation and output encoding is essential to prevent malicious payloads from being interpreted as executable commands. Additionally, deploying a Web Application Firewall (WAF) can provide an additional layer of defense by filtering out known attack patterns before they reach the application server. Regular security assessments, including static code analysis tools configured to detect injection vulnerabilities and dynamic penetration testing, are recommended to identify similar weaknesses in other parts of the system. Maintaining a robust patch management process is critical to ensuring that future updates addressing such high-severity issues are applied promptly.