CVE-2021-42136

Name: CVE-2021-42136
Creator: NVD / NIST
Published: 2022-04-13T16:15:09.563+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9/10EPSS 4.52%

Last modified Jun 17, 2026

CVE-2021-42136 is a critical-severity vulnerability rated 9/10 on the CVSS scale. A stored Cross-Site Scripting (XSS) vulnerability in the Missing Data Codes functionality of REDCap before 11.4.0 allows remote attackers to execute JavaScript code in the client's browser by storing said code as a Missing Data Code value. This can then be leveraged to execute a Cross-Site Request Forgery attack to escalate privileges to administrator.. EPSS estimates a 4.52% chance of exploitation in the next 30 days.

Description

A stored Cross-Site Scripting (XSS) vulnerability in the Missing Data Codes functionality of REDCap before 11.4.0 allows remote attackers to execute JavaScript code in the client's browser by storing said code as a Missing Data Code value. This can then be leveraged to execute a Cross-Site Request Forgery attack to escalate privileges to administrator.

Metrics

CVSS 3.1

9/10

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

EPSS Probability

4.52%

90.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Vanderbilt	Redcap	< 11.4.0

References

http://packetstormsecurity.com/files/166723/REDCap-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
https://redcap.med.usc.edu/_shib/assets/ChangeLog_Standard.pdfRelease Notes, Third Party Advisory
https://www.project-redcap.org/Product
http://packetstormsecurity.com/files/166723/REDCap-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
https://redcap.med.usc.edu/_shib/assets/ChangeLog_Standard.pdfRelease Notes, Third Party Advisory
https://www.project-redcap.org/Product

Timeline

Published: Apr 13, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42136?

How severe is CVE-2021-42136?

CVE-2021-42136 has a CVSS score of 9/10 (CRITICAL severity). The EPSS model estimates a 4.52% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42136?

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-2021-42136?

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

Scan your code now

Source: NVD / NIST