Описание
LiteLLM: Authentication Bypass via Host Header Injection
Impact
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.
Most deployments are not affected. The bypass is blocked by any upstream layer that validates or normalizes Host, such as:
- a CDN or WAF, such as Cloudflare
- a reverse proxy with
server_nameallowlists - a host-based load balancer
LiteLLM Cloud customers are not affected.
Patches
Fixed in 1.84.0. Upgrade to 1.84.0 or later. No configuration change is required.
Workarounds
If upgrading is not immediately possible, place the proxy behind an upstream component that validates or normalizes the Host header before forwarding (a CDN/WAF, a reverse proxy with explicit server_name allowlists, or a cloud load balancer with host-based routing rules), or otherwise restrict network access to the proxy listener.
References
- Patched release:
v1.84.0
Discovery Credit: Le The Thang (KCSC) and Kim Ngoc Chung (One Mount Group)
Ссылки
- https://github.com/BerriAI/litellm/security/advisories/GHSA-4xpc-pv4p-pm3w
- https://nvd.nist.gov/vuln/detail/CVE-2026-49468
- https://access.redhat.com/security/cve/CVE-2026-49468
- https://bugzilla.redhat.com/show_bug.cgi?id=2491520
- https://github.com/BerriAI/litellm/releases/tag/v1.84.0
- https://github.com/advisories/GHSA-4xpc-pv4p-pm3w
- https://github.com/pypa/advisory-database/tree/main/vulns/litellm/PYSEC-2026-388.yaml
- https://pypi.org/project/litellm
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49468.json
Пакеты
litellm
< 1.84.0
1.84.0
EPSS
9.5 Critical
CVSS4
9.8 Critical
CVSS3
CVE ID
Дефекты
Связанные уязвимости
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.
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.
EPSS
9.5 Critical
CVSS4
9.8 Critical
CVSS3