The Zombie Bug — Critical CVE 2025 Story

CISA Alert: 6-Year-Old Sitecore Flaws Are Back (And Why You Should Care)

TL;DR: In March 2025, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) issued an alert about two old vulnerabilities in Sitecore Experience Platform — a popular enterprise CMS — that hackers are exploiting right now. These bugs (tracked as CVE-2021–42237 and CVE-2021–42238) were patched back in 2021, but many organizations haven’t updated, leaving their systems open to attack. In this post, I’ll break down what Sitecore is, who CISA is (and why their warnings matter), what these vulnerabilities mean in plain English (hint: “insecure deserialization” leading to remote code execution), and why keeping your software up-to-date is crucial.

What is Sitecore XP, in Plain English?

Sitecore Experience Platform (XP) is essentially a high-end website management system — think of it as WordPress on steroids for big businesses. It’s an enterprise-level content management system (CMS) used by large organizations (including Fortune 500 companies) to manage website content, digital marketing, and customer data across different channels. Because Sitecore is so powerful and used in mission-critical websites, a security flaw in Sitecore can be a big deal — it could affect banks, governments, or major corporations that rely on it for their web presence.

Who/What is CISA and Why Do Their Alerts Matter?