CVE-2021-23758 — Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
CVE-2021-23758: Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
CISA Known Exploited Vulnerability (KEV)
| Vendor / project | Ajax.NET Professional |
| Product | Ajax.NET Professional |
| Date added | 2026-08-26 |
| Due date | 2026-09-09 |
| Ransomware campaign use | Unknown |
Description
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.
Required action (CISA)
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.
Notes
This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2021-23758
References
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23758
- KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog