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Authentication bypass in LiteLLM proxy via Host header injection

IdentifiersCVE-2026-49468CWE-290

CVE-2026-49468 is a critical authentication bypass vulnerability in the LiteLLM proxy affecting versions prior to 1.84.0. The flaw is caused by improper handling of the HTTP Host header during route determination in the authentication layer. Specifically, the vulnerable logic is in get_request_route() within litellm/proxy/auth/auth_utils.py, where the authentication check derives the effective route from request.url.path. Because Starlette reconstructs request.url.path using the supplied Host header, a crafted Host header can cause the authentication layer to evaluate a different route than the one FastAPI ultimately dispatches. Under these conditions, an unauthenticated attacker can reach protected management routes that should require authentication.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow unauthenticated access to protected LiteLLM management endpoints. Because LiteLLM deployments often act as a central gateway for LLM API traffic and associated provider credentials, exploitation may expose sensitive administrative functionality and could affect confidentiality, integrity, and availability depending on the reachable management actions. The issue is network-exploitable, requires no prior authentication, and does not require user interaction.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, place LiteLLM behind an upstream component that strictly validates or normalizes the Host header before forwarding requests. Examples called out in the supporting content include Cloudflare or similar CDNs/WAFs, reverse proxies with explicit server_name allowlists, and cloud or host-based load balancers enforcing host validation or host-based routing rules. Additionally, restrict network access to the LiteLLM proxy listener to reduce exposure.

Remediation

Patch, then assume compromise.

Upgrade LiteLLM to version 1.84.0 or later, which patches the vulnerability. The available advisory states that no configuration change is required after upgrading.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

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VendorProductType
BerriAILitellmapplication

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Social activity1

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