A flaw was found in oras-go. The auth.Client in oras-go does not properly validate the scheme or host of the realm URL provided in a registry's WWW-Authenticate: Bearer challenge. A remote attacker, operating a malicious registry or performing a man-in-the-middle attack, could exploit this to perform Server-Side Request Forgery (SSRF) against internal networks, potentially disclosing sensitive information. Additionally, the flaw could lead to a Transport Layer Security (TLS) downgrade, causing user credentials to be sent over plaintext.