CVE-2021-23758
Act now ● On CISA KEV — actively exploited
Actively exploited — on the CISA KEV list.
CVSS base
8.1
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
83.6%
99.7th percentile
CISA KEV
Listed
Added 2026-08-26 · patch by 2026-09-09
Weakness / dates
CWE-502
Published 2021-12-03 · modified 2026-08-27
CVSS breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | N | Network |
| Attack Complexity | H | High |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2021-12-03 — Published (NVD)
- 2026-08-26 — Added to CISA KEV (actively exploited)
- 2026-09-09 — CISA patch-by deadline
- 2026-08-27 — Last modified (NVD)
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.
Affected
References
- exploit http://packetstormsecurity.com/files/175677/AjaxPro-Deserialization-Remote-Code-Execution.html
- https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57
- https://snyk.io/vuln/SNYK-DOTNET-AJAXPRO2-1925971
- exploit http://packetstormsecurity.com/files/175677/AjaxPro-Deserialization-Remote-Code-Execution.html
- https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57
- https://snyk.io/vuln/SNYK-DOTNET-AJAXPRO2-1925971
- exploit https://blog.talosintelligence.com/uat-10147-chinese-speaking-adversary-integrates-agentic-ai-into-post-compromise-operations/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-23758