CVE-2021-23758

CVE Enrichment

CVSS: 9.8 CRITICAL
EPSS: 82.58%
EPSS Percentile: 99.66%
CISA KEV: YES — Known Exploited Vulnerability

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.

Technical Details

CVSS Version: 3.1
CNA / NVD Source: report@snyk.io
Published: 04-Dec-2021 03:15
Last Modified: 27-Aug-2026 11:16
EPSS Date: 2026-10-11
CWE: CWE-502

CVSS Vector


            CVSS:3.1                            AV:N /
                            AC:L /
                            PR:N /
                            UI:N /
                            S:U /
                            C:H /
                            I:H /
                            A:H

CISA KEV Details

Date Added: 2026-08-26
Remediation Due: 2026-09-09
Known Ransomware Campaign Use: Unknown
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.
Notes: This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2021-23758

Affected Products / Versions

ajaxpro.2_project / ajaxpro.2
Version / affected range: *
cpe:2.3:a:ajaxpro.2_project:ajaxpro.2:*:*:*:*:*:.net:*:*
michaelschwarz / ajax.net_professional
Version / affected range: * · before (exclusive) 21.10.30.1
cpe:2.3:a:michaelschwarz:ajax.net_professional:*:*:*:*:*:.net:*:*

References

Last enrichment sync: 12-Oct-2026 21:03
Sources: NVD · FIRST EPSS · CISA KEV
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Reported Context (1)

CVE-2021-23758 Recorded Future Identifies 73 High-Impact Vulnerabilities in August, 70 Actively Exploited

CVE (71)

Malware (4)

Threat Actors (1)

Vendors (22)

Products (18)

Tools (7)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.