CVE-2026-47304 in .NET
Summary
by MITRE • 07/14/2026
Improper verification of cryptographic signature in .NET allows an unauthorized attacker to bypass a security feature over a network.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical weakness in the cryptographic signature verification process within the .NET framework that enables attackers to circumvent security controls through network-based attacks. The flaw occurs when the system fails to properly validate digital signatures, allowing malicious actors to inject forged or tampered code into legitimate applications. This improper verification typically stems from insufficient checks during the signature validation phase where the system accepts signatures without adequate cryptographic proof of authenticity.
The technical implementation of this vulnerability often involves bypassing certificate chain validation, weak hash algorithm usage, or inadequate signature format checking within the .NET runtime environment. Attackers can exploit this weakness by crafting malicious payloads that appear to have valid signatures but actually contain unauthorized code modifications. The vulnerability operates at the core cryptographic layer where digital signatures should provide integrity and authenticity guarantees, yet the flawed verification process allows forged signatures to be accepted as legitimate.
From an operational perspective, this vulnerability creates significant risk across multiple attack vectors including man-in-the-middle scenarios, supply chain attacks, and remote code execution opportunities. Network-based exploitation becomes particularly dangerous because attackers can leverage existing network connections to deliver malicious payloads without requiring local system access. The impact extends beyond individual applications to potentially compromise entire deployment environments where .NET applications are used for critical security functions.
The attack surface is further expanded by the widespread adoption of .NET across enterprise environments, making this vulnerability particularly dangerous in corporate networks where attackers can leverage it to establish persistent access. This weakness directly relates to common attack patterns documented in the mitre ATT&CK framework under the execution and privilege escalation categories, where adversaries exploit software vulnerabilities to run malicious code with elevated privileges.
Security controls should focus on implementing robust certificate validation procedures, ensuring proper signature verification at multiple levels, and deploying network monitoring solutions to detect anomalous signature validation behavior. Organizations must also enforce strict certificate management policies, regularly update cryptographic libraries, and implement additional layers of security such as code integrity checks and application whitelisting. The vulnerability aligns with CWE-347 which addresses improper certificate validation, making it essential for organizations to address both the immediate technical flaw and broader cryptographic security practices.
Mitigation strategies should include comprehensive patch management programs specifically targeting .NET cryptographic components, implementation of additional signature verification layers beyond the default framework behavior, and regular security assessments focused on cryptographic implementation. Network segmentation and monitoring solutions can help detect unusual signature validation patterns that might indicate exploitation attempts, while secure coding practices should emphasize proper error handling and validation of all cryptographic inputs to prevent similar vulnerabilities from emerging in custom applications.