CVE-2023-27534: Path Traversal in curl SFTP Tilde Expansion

curl's SFTP implementation contains a path traversal vulnerability when handling tilde () expansion in SFTP URLs. The vulnerability allows an attacker to read arbitrary files outside the user's home directory by using path traversal sequences (../) in SFTP URLs after the tilde () prefix. A crafted URL like sftp://user@host/~/../../etc/passwd would allow reading /etc/passwd instead of a file in the user's home directory.