Actively exploited in the wild
Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
Ajax.NET Professional - Ajax.NET Professional · Listed in the CISA KEV since 2026-08-26. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2021-23758
HighCVSS 8.1KEVExploitation Probability (EPSS)
Very high risk100th percentile - higher than 100% of all known CVEs
Summary
All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data, which can be abused to gain remote code execution.
Risk Assessment
An attacker can exploit deserialization to execute arbitrary code in the application context, potentially leading to server compromise and access to sensitive data.
Recommendation
Discontinue use of ajaxpro.2 and migrate to a secure alternative or apply mitigations such as restricting deserialization to trusted types.
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Original NVD description (English source)
All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS