Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-43853

19
FAUCET Score

CVE-2021-43853 is a JavaScript object injection vulnerability in Ajax.NET Professional (AjaxPro) versions prior to 21.12.22.1, an AJAX framework for Microsoft ASP.NET. This flaw can lead to cross-site scripting (XSS) when a malicious user manipulates JSON input. With a CVSS score of 5.4 (Medium), it requires low privileges and user interaction, impacting confidentiality and integrity. There is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in CISA's KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
< 21.12.22.1CPE matchmatch criteria
cpe:2.3:a:ajax.net_professional_project:ajax.net_professional:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.7HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.3
Impact Score
5.8
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.82%
Probability of exploitation in next 30 days
EPSS Percentile
53.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0082 is in the 89th percentile among its peer group of 15,239 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
nugetpatch availablevia ghsa
Product: AjaxNetProfessionalFixed in: 21.12.22.1

Vendor Advisories (1)

nugetGHSA-5q7q-qqw2-hjq7high

AjaxNetProfessional deserializes arbitrary JavaScript objects

Jan 6, 2022

References

github.com / michaelschwarz/Ajax.NET-Professional/commit/c89e39b9679fcb8ab6644fe21cc7e652cb615e2b
PatchThird Party Advisory
github.com / michaelschwarz/Ajax.NET-Professional/releases/tag/v21.12.22.1
Release NotesThird Party Advisory
github.com / michaelschwarz/Ajax.NET-Professional/security/advisories/GHSA-5q7q-qqw2-hjq7
MitigationThird Party Advisory