KEV 2026.09.231,721 entries+8 in 7d8 open federal deadlinesas of / search ? keys
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KEV / Record

CVE-2021-23758: Ajax.NET Professional Deserialization of Untrusted Data Vulnerability

Catalog
2026.09.23
Added
2026-08-26

Answer CVE-2021-23758 is in CISA's Known Exploited Vulnerabilities catalog. It was added on 2026-08-26, and US federal civilian agencies must act on it by 2026-09-09.

DCISA 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.

ARequired 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.

RNotes and references

FRecord

CVE
CVE-2021-23758
Vendor
Ajax.NET Professional (1 entry in KEV)
Product
Ajax.NET Professional (1 entry)
Added to KEV
Federal due date
Past due date (2026-09-09)
Remediation window
14 days
Known ransomware use
Unknown (not confirmed by CISA)

NVD record · CVE.org record

This record repeats CISA's entry and is excluded from search indexes until an analyst note is added.

Source: CISA KEV catalog v2026.09.23, released 2026-09-23. Windows end 2026-09-23.

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