CVE-2021-23758

Deserialization of Untrusted Data

  • High 8.1
  • Exploited: added to CISA KEV 26 Aug 2026

Description

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.

Key facts

Published
3 Dec 2021
Last changed
27 Aug 2026
Assigned by
snyk
KEV added
26 Aug 2026
KEV fix due
9 Sep 2026
EPSS
82.578% likely to be exploited in the next 30 days, higher than 99.672% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 8.1CVSS 3.1, Highfrom the CNA (snyk)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

What to do

  • 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.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
n/aAjaxPro.2
  • 0 up to but excluding unspecified (affected)

Timeline

  1. 3 Dec 2021 Published
  2. 26 Aug 2026 CVE-2021-23758 added to CISA KEV
  3. 26 Aug 2026 Added to the CISA KEV catalogue

Weakness

References