What’s Vulnerable › Vulnerabilities

CVE-2021-43853: Cross-Site Scripting in AjaxNetProfessional

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-22 · updated 2026-06-17
• Weakness: CWE-79

Description

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.

Affected products

• Ajax.Net Professional Project Ajax.Net Professional: before 21.12.22.1 — fixed in 21.12.22.1

How to fix

Upgrade to a fixed version: Ajax.Net Professional Project Ajax.Net Professional 21.12.22.1. Check the vendor advisory for mitigations.

References

• https://github.com/michaelschwarz/Ajax.NET-Professional/commit/c89e39b9679fcb8ab6644fe21cc7e652cb615e2b
• https://github.com/michaelschwarz/Ajax.NET-Professional/releases/tag/v21.12.22.1
• https://github.com/michaelschwarz/Ajax.NET-Professional/security/advisories/GHSA-5q7q-qqw2-hjq7
• https://github.com/michaelschwarz/Ajax.NET-Professional/commit/c89e39b9679fcb8ab6644fe21cc7e652cb615e2b
• https://github.com/michaelschwarz/Ajax.NET-Professional/releases/tag/v21.12.22.1
• https://github.com/michaelschwarz/Ajax.NET-Professional/security/advisories/GHSA-5q7q-qqw2-hjq7

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