CVE-2021-43853

Name: CVE-2021-43853
Creator: NVD / NIST
Published: 2021-12-22T21:15:07.527+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.82%

Last modified Jun 17, 2026

CVE-2021-43853 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 0.82% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.4/10

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

EPSS Probability

0.82%

52.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Ajax.Net Professional Project	Ajax.Net Professional	< 21.12.22.1

References

https://github.com/michaelschwarz/Ajax.NET-Professional/commit/c89e39b9679fcb8ab6644fe21cc7e652cb615e2bPatch, Third Party Advisory
https://github.com/michaelschwarz/Ajax.NET-Professional/releases/tag/v21.12.22.1Release Notes, Third Party Advisory
https://github.com/michaelschwarz/Ajax.NET-Professional/security/advisories/GHSA-5q7q-qqw2-hjq7Mitigation, Third Party Advisory
https://github.com/michaelschwarz/Ajax.NET-Professional/commit/c89e39b9679fcb8ab6644fe21cc7e652cb615e2bPatch, Third Party Advisory
https://github.com/michaelschwarz/Ajax.NET-Professional/releases/tag/v21.12.22.1Release Notes, Third Party Advisory
https://github.com/michaelschwarz/Ajax.NET-Professional/security/advisories/GHSA-5q7q-qqw2-hjq7Mitigation, Third Party Advisory

Timeline

Published: Dec 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43853?

How severe is CVE-2021-43853?

CVE-2021-43853 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.82% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43853?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-43853?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST