Coverage › CVE-2021-23758
CVE-2021-23758 Unmapped
Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
- Vendor / product
- Ajax.NET Professional — Ajax.NET Professional
- Description (CISA)
- 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.
- Added to KEV
- 2026-08-26 — after the latest CTID mapping snapshot (2025-07-28)
- Due date
- 2026-09-09
- 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.
- Known ransomware use
- Unknown
- CWE
- CWE-502
- CISA 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 - Elsewhere
- cve.org · NVD · CISA KEV · JSON
ATT&CK techniques
No public source states how this vulnerability is exploited in ATT&CK terms.
The only authoritative CVE → ATT&CK mapping in the open — CTID's Mappings Explorer, pinned to a KEV snapshot of 2025-07-28 and ATT&CK 16.1 — does not include CVE-2021-23758. This entry was added to KEV on 2026-08-26, after that snapshot; of the 291 entries added since, 0 have a mapping. CISA's catalogue carries no technique field. kevmap does not infer techniques from the CWE (CWE-502) — here is why — and does not guess.
This page will change state automatically if a mapping is published. What is shown above is everything CISA publishes about the entry.