1. Cleus
  2. Zero-days
  3. CVE-2021-42237
Exploited in the wildUsed by ransomwareServers & business softwareWork IT

CVE-2021-42237 Sitecore XP: unsafe data loading

In plain words: The program unpacks saved data from outside without checking it is safe. Usually lets an attacker run code on the server.

Confirmed exploited by CISA on · US federal patch deadline Apr 15, 2022

What to do

  1. Install Sitecore's security update for XP. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Keep a list of every internet-facing server you run so nothing is forgotten.
  3. Patch anything in this catalog first, ahead of normal patch cycles.
  4. Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.

The details

Official name
Sitecore XP Remote Command Execution Vulnerability
Product
Sitecore XP
CISA description
Sitcore XP contains an insecure deserialization vulnerability which can allow for remote code execution.
Type of flaw
Unsafe data loading (CWE-502)
Confirmed exploited
Mar 25, 2022 — known to be used in ransomware attacks
US federal patch deadline
Apr 15, 2022

Ask Cleus about it

Ask about a vulnerability, an update, a weird message, or the news. Plain-word answers, free, no account.

Answering about CVE-2021-42237 ·

Questions about CVE-2021-42237

Is CVE-2021-42237 being exploited?

Yes. CISA added CVE-2021-42237 to its Known Exploited Vulnerabilities catalog on Mar 25, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.

How do I fix CVE-2021-42237?

Install Sitecore's security update for XP. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.

Am I affected by CVE-2021-42237?

Only if you use Sitecore XP. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

Other exploited Sitecore vulnerabilities

Newest in the catalog

Search every known exploited vulnerability →