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Findings

CVE-2021-23758

Ajax.NET Professional Deserialization of Untrusted Data Vulnerability

Published Dec 3, 2021 · updated Aug 26, 2026 · Ajax.NET Professional Ajax.NET Professional

Ajax.NET Professional (AjaxPro) contains a deserialization of untrusted data vulnerability that could allow for remote code execution via arbitrary .NET classes. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 3, 2021 · Catalog

    Detected

    Ajax.NET Professional (AjaxPro) contains a deserialization of untrusted data vulnerability that could allow for remote code execution via arbitrary .NET classes. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

  2. Aug 26, 2026 · CISA KEV

    Known exploited

    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

  3. Aug 26, 2026 · Catalog

    Updated

    Ajax.NET Professional (AjaxPro) contains a deserialization of untrusted data vulnerability that could allow for remote code execution via arbitrary .NET classes. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

  4. Sep 9, 2026 · CISA KEV

    Remediation due

    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

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.

CISA due date Sep 9, 2026

Affected

  • cpe ajaxpro.2 project/ajaxpro.2version unspecified
  • cpe michaelschwarz/ajax.net professionalversion unspecified
  • vendor Ajax.NET Professional Ajax.NET Professionalversion unspecified

Sources

  • CISA KEVCVE-2021-23758

    Ajax.NET Professional (AjaxPro) contains a deserialization of untrusted data vulnerability that could allow for remote code execution via arbitrary .NET classes. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

    cisa.gov
  • CVE.orgCVE-2021-23758

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2021-23758

    30-day exploitation probability 82.6%

    first.org
  • Metasploit Modulesexploit_windows/http/ajaxpro_deserialization_rce

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDCVE-2021-23758

    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.

    nvd.nist.gov
  • Packet Storm Securityhttp://packetstormsecurity.com/files/175677/AjaxPro-Deserialization-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References