CVE-2026-49468CWE-290

LiteLLM: Authentication Bypass via Host Header Injection

Critical · published June 22, 2026

CVSS v4.0
9.5
EPSS
3%
Percentile
87.4
In the wild
Unconfirmed
What it is

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, a Host-header parsing flaw in the LiteLLM proxy could, under specific conditions, allow unauthenticated access to protected management routes. The auth layer derived the effective route from request.url.path in litellm/proxy/auth/auth_utils.py::get_request_route(), which Starlette reconstructs from the Host header. A crafted Host could therefore make the auth gate evaluate a different route from the one FastAPI dispatched. This vulnerability is fixed in 1.84.0.

The record
Technical detail
CVSS v4.0
9.5 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
EPSS
0.03033 · 87.4th percentile
Weakness
CWE-290 · Authentication Bypass by Spoofing
Published
2026-06-22T20:37Z
EPSS history
Timeline
  • 22 JUN 20:37Z
    LiteLLM: Authentication Bypass via Host Header Injection
    cvelistv5