Security Operations
Threat Intelligence
๐Ÿ”Ž
โ“

CVE-2021-23758 - Ajax.NET Professional Deserialization of Untrusted Data Vulnerability (known exploited)

Added to CISA KEV on 2026-08-26. 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.
CRITICAL CISA KEV ACTIVELY EXPLOITED
Severity & confidence
Source severitycritical
Platform severitycritical
Confidencehigh
Exploitationactively exploited
CVSS-
Affected
ProductsAjax.NET Professional
Reporting sources (1)
CISA - Known Exploited Vulnerabilities
Open source โ†—
๐ŸŽฏ Why should I care?
  • On the CISA Known Exploited Vulnerabilities list.
  • Credible sources report active exploitation in the wild.
Timeline & provenance
Published2026-08-26T00:00:00
Last updated2026-10-21T04:58:06
Ingested2026-08-26T17:43:10
FreshnessNEAR-REAL-TIME
Threat typeexploitation
Recommended action
Apply the vendor-supplied patch immediately. Review vendor and CISA guidance for detection and mitigation.
Next steps
  1. Identify affected systems in your environment.
  2. Apply the vendor patch or mitigation guidance.
  3. Review logs for indicators described in the advisory.
  4. Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: gov ยท Original: CISA - Known Exploited Vulnerabilities