CVE-2021-43853 Cross-Site Scripting in AjaxNetProfessional
Attackers can execute arbitrary JavaScript via malicious JSON input in Ajax.NET Professional, potentially compromising user sessions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-43853?
CVE-2021-43853 is a high-severity cross-site scripting vulnerability in michaelschwarz Ajax.NET-Professional, published on 22 Dec 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2021-43853?
2 open source packages ship an affected version, including AjaxNetProfessional. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
AjaxNetProfessional NuGet | All versions | 21.12.22.1 |
AjaxNetProfessional NuGet | All versions | 21.12.22.1 |
Products include Ajax.net Professional Project Ajax.net Professional.
How do I fix CVE-2021-43853?
Upgrade AjaxNetProfessional to 21.12.22.1 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2021-43853 being exploited?
There is no known exploitation of CVE-2021-43853 in the wild and no public exploit code.
Sources
Also known as GHSA-5q7q-qqw2-hjq7.