LiteLLM bug lets attackers bypass auth via Host header, CVSS 9.5

A critical vulnerability, CVE-2026-49468, has been identified in LiteLLM, an open-source AI gateway product. This flaw allows for authentication bypass via a Host header injection, achieving a CVSS rating of 9.5. The vulnerability affects versions below 1.84.0 and is exploitable if the proxy doesn't have upstream validation in place. The issue has been addressed in version 1.84.0, and users are urged to update promptly. Most installations are not at risk due to upstream defenses like CDNs or WAFs. The flaw was reported responsibly by researchers from KCSC and One Mount Group.