HIGH CISA-KEV ACTIVELY EXPLOITED PoC
CVE-2021-23758
Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
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.
Affected Products
- Ajax.NET Professional: Ajax.NET Professional
References
- https://nvd.nist.gov/vuln/detail/CVE-2021-23758
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
This high severity vulnerability was published on 2026-08-26 via CISA-KEV. ⚠ This vulnerability is in the CISA Known Exploited Vulnerabilities (KEV) catalog — it is being actively exploited in the wild. 🚨 A public proof-of-concept exploit is available on GitHub. EPSS score: 89.1% (top 0% of all CVEs by exploitation probability). Affected: Ajax.NET Professional: Ajax.NET Professional.
Risk Timeline
CVE Disclosed2026-08-26 · 0 days ago
Public PoC Exploit AvailableWeaponised proof-of-concept code is publicly accessible
CISA KEV — Actively ExploitedU.S. federal agencies required to patch · confirmed threat-actor activity
Remediation Resources
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