CriticalCISA KEVAug 26, 2026

CVE-2021-23758: Ajax.NET Professional Ajax.NET Professional added to CISA KEV

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.

Why it matters

The weakness can enable direct compromise with limited attacker prerequisites, making internet-facing assets the first place to look.

What defenders should do

Identify affected versions, prioritize internet-facing systems, and apply the vendor remediation.

Verify at the source

CyberKit curates and prioritizes; the source remains authoritative. Read the original advisory at www.cisa.gov →

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