hardlink — Vulnerabilities & Security Advisories 3

Hardlink serves as a file system feature allowing multiple directory entries to reference the same inode, primarily used for efficient storage and data organization. Historically, vulnerabilities in hardlink implementations have frequently involved privilege escalation, where attackers create hardlinks to sensitive files to bypass access controls, and local arbitrary code execution through insecure handling of hardlinked files. Notable security characteristics include its potential for race conditions during file operations and its exploitation in container escape scenarios. While only three CVEs are documented, these often highlight risks in file permission handling and symlink attacks, particularly in systems with inadequate hardlink restrictions between users or privilege boundaries.