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)
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | litellm | < 1.84.0 | 1.84.0 |
Referencias
- https://github.com/BerriAI/litellm/security/advisories/GHSA-4xpc-pv4p-pm3w
- https://github.com/BerriAI/litellm
- https://github.com/BerriAI/litellm/releases/tag/v1.84.0
- https://pypi.org/project/litellm
- https://github.com/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/pypa/advisory-database/tree/main/vulns/litellm/PYSEC-2026-388.yaml
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49468.json
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Debilidad (CWE)
CWE-290- Plataforma
- Python (PyPI)
- Paquete
litellm- Publicada
- 16.06.2026
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-388 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4xpc-pv4p-pm3w - CC BY 4.0
Historial de vulnerabilidades: litellm
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 42
- Primera → última
- 04.2024 09.2026
- Sin corrección
- 14
- Explotada en ataques
- 3
Distribución por gravedad
- Crítica 7
- Alta 17
- Media 8
- Baja 9
- Sin evaluar 1
Divulgaciones por año
- 2024: 8
- 2025: 6
- 2026: 28
-
LiteLLM: Authentication Bypass via Host Header Injection esta entrada
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