Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
n/a — AjaxPro.2
All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.
8.1
83.6%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- Dec 3, 2021
- Modified
- Aug 27, 2026
- Added to KEV
- Aug 26, 2026
- Federal patch due
- Sep 9, 2026
CISA required 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
1 foundWeaponization
Public repositories whose name or description references CVE-2021-23758, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
References
How this class of flaw gets exploited
Frequently asked questions
What is CVE-2021-23758?
All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.
How severe is CVE-2021-23758?
CVE-2021-23758 has a CVSS base score of 8.1 out of 10 (CVSS 3.1).
Is CVE-2021-23758 actively exploited in the wild?
Yes. CVE-2021-23758 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Aug 26, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2021-23758?
83.6% - meaning FIRST.org's EPSS model estimates a 83.6% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2021-23758?
We found 1 public GitHub repository referencing CVE-2021-23758, though none matched a known Nuclei template or Metasploit module at last check. Review each one before relying on it - see the proof-of-concept section above.
What type of vulnerability is CVE-2021-23758?
CVE-2021-23758 is classified under CWE-502 (CWE-502 Deserialization of Untrusted Data).
Cross-checked against
Impactr finds and proves whether CVE-2021-23758 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.