CVE-2026-49468: unauthenticated access in LiteLLM proxy

Host-header parsing flaw in LiteLLM proxy (pre 1.84.0) enables unauthenticated management access.

CVE-2026-49468 is a Host-header parsing flaw in LiteLLM proxy (versions < 1.84.0), an AI gateway for managing traffic to LLM services like OpenAI-compatible APIs. The vulnerability allows authentication bypass to access management routes. The auth layer reads request.url.path, reconstructed by Starlette from the Host header, creating misalignment with FastAPI's dispatch: a crafted Host can make the gateway evaluate a different route.

The vulnerability carries CVSS 9.8 (critical). Patch available since 2026-06-22 in version 1.84.0. No public exploitation signals in available data, but LiteLLM's widespread use makes it plausible that unpatched systems have already been compromised during 4 months of exposure.

Immediate actions: 1) Check if LiteLLM is in production. 2) If yes, update to 1.84.0+ without delay. 3) Audit management route logs for the past 4 months for unauthorized access patterns. 4) Verify authentication on all critical routes in patched systems.

At a glance

What: Host-header parsing flaw in LiteLLM proxy (versions < 1.84.0) enabling authentication bypass to management routes. The auth layer reads request.url.path reconstructed from Host header, allowing an attacker to send a crafted Host to evaluate a different route from the one FastAPI actually dispatches.
Severity: CVSS 9.8 (critical). Unauthenticated access to gateway management routes, potential configuration compromise and access to sensitive API credentials.
Affected versions: LiteLLM versions prior to 1.84.0
Fix: Update to LiteLLM 1.84.0 or later where the vulnerability is fixed and Host header validation has been implemented.
Status: Patch available since 2026-06-22 (version 1.84.0). No signals of public active exploitation in available data. Vulnerability known for approximately 4 months.
Action: 1) Check if LiteLLM is in production. 2) If yes, update to 1.84.0+ within 2 weeks. 3) Audit management route access logs for the past 4 months (from 2026-06-22) for unauthorized access patterns. 4) Verify authentication is active on all critical routes.

Sources: NVD, CVE-2026-49468

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