CVE-2021-42237

Name: CVE-2021-42237
Creator: NVD / NIST
Published: 2021-11-05T10:15:08.24+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 99.21%

Last modified Jun 17, 2026

CVE-2021-42237 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.. CISA has confirmed active exploitation in the wild. EPSS estimates a 99.21% chance of exploitation in the next 30 days.

Description

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

99.21%

99.9th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Apr 15, 2022.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Sitecore	Experience Platform	7.5
Sitecore	Experience Platform	8.0
Sitecore	Experience Platform	8.1
Sitecore	Experience Platform	8.2

References

http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.htmlThird Party Advisory, VDB Entry
http://sitecore.comVendor Advisory
https://blog.assetnote.io/2021/11/02/sitecore-rce/Exploit, Third Party Advisory
https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776Vendor Advisory
http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.htmlThird Party Advisory, VDB Entry
http://sitecore.comVendor Advisory
https://blog.assetnote.io/2021/11/02/sitecore-rce/Exploit, Third Party Advisory
https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42237US Government Resource

Timeline

Published: Nov 5, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-42237?

How severe is CVE-2021-42237?

CVE-2021-42237 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 99.21% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-42237?

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-2021-42237?

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

Scan your code now

Source: NVD / NIST