Log4Shell (2021)
Researchers disclosed a critical remote code execution vulnerability in Log4j, a Java logging library used by millions of applications. Attackers could exploit it with a single crafted string, and scans for vulnerable systems began within hours.
Organizations scrambled to patch, and the US government ordered federal agencies to fix the flaw within days.
Log4Shell became a benchmark for critical software supply chain vulnerabilities, prompting new scrutiny of open-source dependencies.
Like php2shell, Log4Shell affected a foundational piece of software used across the internet, forcing a global patching effort.
