GHSA-4XPC-PV4P-PM3W

Vulnerability from github – Published: 2026-06-16 23:38 – Updated: 2026-06-16 23:38
VLAI
Summary
LiteLLM: Authentication Bypass via Host Header Injection
Details

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_name allowlists
  • 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

Discovery Credit: Le The Thang (KCSC) and Kim Ngoc Chung (One Mount Group)

Severity
9.5 (Critical)
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "litellm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.84.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49468"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-16T23:38:26Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Impact\n\nA Host-header parsing flaw in the LiteLLM proxy could, under specific conditions, allow unauthenticated access to protected management routes.\n\nThe 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.\n\n**Most deployments are not affected.** The bypass is blocked by any upstream layer that validates or normalizes `Host`, such as:\n\n- a CDN or WAF, such as Cloudflare\n- a reverse proxy with `server_name` allowlists\n- a host-based load balancer\n\n**LiteLLM Cloud customers are not affected.**\n\n### Patches\n\nFixed in **`1.84.0`**. Upgrade to `1.84.0` or later. No configuration change is required.\n\n### Workarounds\n\nIf 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.\n\n### References\n\n- Patched release: [`v1.84.0`](https://github.com/BerriAI/litellm/releases/tag/v1.84.0)\n\n**Discovery Credit**: Le The Thang (KCSC) and Kim Ngoc Chung (One Mount Group)",
  "id": "GHSA-4xpc-pv4p-pm3w",
  "modified": "2026-06-16T23:38:26Z",
  "published": "2026-06-16T23:38:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/BerriAI/litellm/security/advisories/GHSA-4xpc-pv4p-pm3w"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/BerriAI/litellm"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BerriAI/litellm/releases/tag/v1.84.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "LiteLLM: Authentication Bypass via Host Header Injection"
}


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