CVE intelligence and bounded remediation
CVE-2021-43853 — Ajax.NET Professional (AjaxPro) is an AJAX framework available for Microsoft ASP.NET
Ajax.NET Professional (AjaxPro) is an AJAX framework available for Microsoft ASP.NET. Affected versions of this package are vulnerable to JavaScript object injection which may result in cross site scripting when leveraged by a malicious user. The affected core relates to JavaScript object creation when parsing json input. Releases before version 21.12.22.1 are affected. A workaround exists that replaces one of the core JavaScript files embedded in the library. See the GHSA-5q7q-qqw2-hjq7 for workaround details.
- Severity
- High
- CVSS
- 8.7 (3.1)
- Published
- 2021-12-22
- CISA KEV
- Not currently listed
- Ecosystem
- windows/system
- Weaknesses
- CWE-79, CWE-502
Affected products
- ajax.net_professional_project / ajax.net_professional
Matched remediation archetype
Unsafe deserialization and object reconstruction
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Check exposure
- Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
- Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
- Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.
Remediate safely
- Replace native object deserialization with a data-only format and explicit schema validation.
- If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
- Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.
Authoritative sources
Complete CVE record and remediation plan
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