Several high-profile vulnerabilities target Magento 1.9.x, with many having public code available on platforms like GitHub and Exploit-DB .
One of the most famous exploits for this version, it allows unauthenticated attackers to gain full administrative access by exploiting an SQL injection vulnerability in the /admin/ path. A well-known Python script for this can be found in repositories like joren485/Magento-Shoplift-SQLI.
Search for "Magento" in the GitHub Advisory Database to find CVE-mapped vulnerabilities and official security summaries. magento 1900 exploit github link
For versions below 1.9.0.1, authenticated users with certain permissions could execute remote code via import features or malicious XML layout updates. How to Find Exploit Links on GitHub
A critical vulnerability where attackers can execute arbitrary code on the server through the PHP mail() function. GitHub security advisories like GHSA-26hq-7286-mg8f provide details on how this affects Zend Framework 1, which Magento 1 uses. Several high-profile vulnerabilities target Magento 1
Running Magento 1.9.0.0 today is highly risky. To secure your site, consider the following:
If you are performing security research or auditing a legacy site, you can find exploit code and advisories using specific searches on GitHub: Search for "Magento" in the GitHub Advisory Database
joren485/Magento-Shoplift-SQLI: Proof of Concept ... - GitHub
Repositories such as gwillem/magento-security-resources track community-sourced security checklists and vulnerability databases. Protection and Mitigation