Common Weakness Enumeration

CWE-1385

Allowed

Missing Origin Validation in WebSockets

Abstraction: Variant · Status: Incomplete

API response cwe.mitre.org

The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid.

73 vulnerabilities reference this CWE, most recent first.

GHSA-VG6X-RCGG-RJX6

Vulnerability from github – Published: 2025-01-21 19:52 – Updated: 2025-02-07 17:38

Summary

Websites were able to send any requests to the development server and read the response in vite

Details

Summary

Vite allowed any websites to send any requests to the development server and read the response due to default CORS settings and lack of validation on the Origin header for WebSocket connections.

[!WARNING] This vulnerability even applies to users that only run the Vite dev server on the local machine and does not expose the dev server to the network.

Upgrade Path

Users that does not match either of the following conditions should be able to upgrade to a newer version of Vite that fixes the vulnerability without any additional configuration.

Using the backend integration feature
Using a reverse proxy in front of Vite
Accessing the development server via a domain other than localhost or *.localhost
Using a plugin / framework that connects to the WebSocket server on their own from the browser

Using the backend integration feature

If you are using the backend integration feature and not setting server.origin, you need to add the origin of the backend server to the server.cors.origin option. Make sure to set a specific origin rather than *, otherwise any origin can access your development server.

Using a reverse proxy in front of Vite

If you are using a reverse proxy in front of Vite and sending requests to Vite with a hostname other than localhost or *.localhost, you need to add the hostname to the new server.allowedHosts option. For example, if the reverse proxy is sending requests to http://vite:5173, you need to add vite to the server.allowedHosts option.

Accessing the development server via a domain other than `localhost` or `*.localhost`

You need to add the hostname to the new server.allowedHosts option. For example, if you are accessing the development server via http://foo.example.com:8080, you need to add foo.example.com to the server.allowedHosts option.

Using a plugin / framework that connects to the WebSocket server on their own from the browser

If you are using a plugin / framework, try upgrading to a newer version of Vite that fixes the vulnerability. If the WebSocket connection appears not to be working, the plugin / framework may have a code that connects to the WebSocket server on their own from the browser.

In that case, you can either:

fix the plugin / framework code to the make it compatible with the new version of Vite
set legacy.skipWebSocketTokenCheck: true to opt-out the fix for [2] while the plugin / framework is incompatible with the new version of Vite
When enabling this option, make sure that you are aware of the security implications described in the impact section of [2] above.

Mitigation without upgrading Vite

[1]: Permissive default CORS settings

Set server.cors to false or limit server.cors.origin to trusted origins.

[2]: Lack of validation on the Origin header for WebSocket connections

There aren't any mitigations for this.

[3]: Lack of validation on the Host header for HTTP requests

Use Chrome 94+ or use HTTPS for the development server.

Details

There are three causes that allowed malicious websites to send any requests to the development server:

[1]: Permissive default CORS settings

Vite sets the Access-Control-Allow-Origin header depending on server.cors option. The default value was true which sets Access-Control-Allow-Origin: *. This allows websites on any origin to fetch contents served on the development server.

Attack scenario:

The attacker serves a malicious web page (http://malicious.example.com).
The user accesses the malicious web page.
The attacker sends a fetch('http://127.0.0.1:5173/main.js') request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that's not the case for the reasons above.
The attacker gets the content of http://127.0.0.1:5173/main.js.

[2]: Lack of validation on the Origin header for WebSocket connections

Vite starts a WebSocket server to handle HMR and other functionalities. This WebSocket server did not perform validation on the Origin header and was vulnerable to Cross-Site WebSocket Hijacking (CSWSH) attacks. With that attack, an attacker can read and write messages on the WebSocket connection. Vite only sends some information over the WebSocket connection (list of the file paths that changed, the file content where the errored happened, etc.), but plugins can send arbitrary messages and may include more sensitive information.

Attack scenario:

The attacker serves a malicious web page (http://malicious.example.com).
The user accesses the malicious web page.
The attacker runs new WebSocket('http://127.0.0.1:5173', 'vite-hmr') by JS in that malicious web page.
The user edits some files.
Vite sends some HMR messages over WebSocket.
The attacker gets the content of the HMR messages.

[3]: Lack of validation on the Host header for HTTP requests

Unless server.https is set, Vite starts the development server on HTTP. Non-HTTPS servers are vulnerable to DNS rebinding attacks without validation on the Host header. But Vite did not perform validation on the Host header. By exploiting this vulnerability, an attacker can send arbitrary requests to the development server bypassing the same-origin policy.

The attacker serves a malicious web page that is served on HTTP (http://malicious.example.com:5173) (HTTPS won't work).
The user accesses the malicious web page.
The attacker changes the DNS to point to 127.0.0.1 (or other private addresses).
The attacker sends a fetch('/main.js') request by JS in that malicious web page.
The attacker gets the content of http://127.0.0.1:5173/main.js bypassing the same origin policy.

Impact

[1]: Permissive default CORS settings

Users with the default server.cors option may:

get the source code stolen by malicious websites
give the attacker access to functionalities that are not supposed to be exposed externally
Vite core does not have any functionality that causes changes somewhere else when receiving a request, but plugins may implement those functionalities and servers behind server.proxy may have those functionalities.

[2]: Lack of validation on the Origin header for WebSocket connections

All users may get the file paths of the files that changed and the file content where the error happened be stolen by malicious websites.

For users that is using a plugin that sends messages over WebSocket, that content may be stolen by malicious websites.

For users that is using a plugin that has a functionality that is triggered by messages over WebSocket, that functionality may be exploited by malicious websites.

[3]: Lack of validation on the Host header for HTTP requests

Users using HTTP for the development server and using a browser that is not Chrome 94+ may:

get the source code stolen by malicious websites
give the attacker access to functionalities that are not supposed to be exposed externally
Vite core does not have any functionality that causes changes somewhere else when receiving a request, but plugins may implement those functionalities and servers behind server.proxy may have those functionalities.

Chrome 94+ users are not affected for [3], because sending a request to a private network page from public non-HTTPS page is forbidden since Chrome 94.

Related Information

Safari has a bug that blocks requests to loopback addresses from HTTPS origins. This means when the user is using Safari and Vite is listening on lookback addresses, there's another condition of "the malicious web page is served on HTTP" to make [1] and [2] to work.

PoC

[2]: Lack of validation on the Origin header for WebSocket connections

I used the react template which utilizes HMR functionality.

npm create vite@latest my-vue-app-react -- --template react

Then on a malicious server, serve the following POC html:

<!doctype html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <title>vite CSWSH</title>
    </head>
    <body>
        <div id="logs"></div>
        <script>
            const div = document.querySelectorAll('#logs')[0];
            const ws = new WebSocket('ws://localhost:5173','vite-hmr');
            ws.onmessage = event => {
                const logLine = document.createElement('p');
                logLine.innerHTML = event.data;
                div.append(logLine);
            };
        </script>
    </body>
</html>

Kick off Vite

npm run dev

Load the development server (open http://localhost:5173/) as well as the malicious page in the browser.
Edit src/App.jsx file and intentionally place a syntax error
Notice how the malicious page can view the websocket messages and a snippet of the source code is exposed

Here's a video demonstrating the POC:

https://github.com/user-attachments/assets/a4ad05cd-0b34-461c-9ff6-d7c8663d6961

Severity

6.5 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 6.0.8"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vite"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.0"
            },
            {
              "fixed": "6.0.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.4.11"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vite"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.4.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.5.5"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vite"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.5.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-24010"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1385",
      "CWE-346",
      "CWE-350"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-01-21T19:52:55Z",
    "nvd_published_at": "2025-01-20T16:15:28Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nVite allowed any websites to send any requests to the development server and read the response due to default CORS settings and lack of validation on the Origin header for WebSocket connections.\n\n\u003e [!WARNING]\n\u003e This vulnerability even applies to users that only run the Vite dev server on the local machine and does not expose the dev server to the network.\n\n### Upgrade Path\nUsers that does not match either of the following conditions should be able to upgrade to a newer version of Vite that fixes the vulnerability without any additional configuration.\n\n- Using the backend integration feature\n- Using a reverse proxy in front of Vite\n- Accessing the development server via a domain other than `localhost` or `*.localhost`\n- Using a plugin / framework that connects to the WebSocket server on their own from the browser\n\n#### Using the backend integration feature\nIf you are using the backend integration feature and not setting [`server.origin`](https://vite.dev/config/server-options.html#server-origin), you need to add the origin of the backend server to the [`server.cors.origin`](https://github.com/expressjs/cors#configuration-options) option. Make sure to set a specific origin rather than `*`, otherwise any origin can access your development server.\n\n#### Using a reverse proxy in front of Vite\nIf you are using a reverse proxy in front of Vite and sending requests to Vite with a hostname other than `localhost` or `*.localhost`, you need to add the hostname to the new [`server.allowedHosts`](https://vite.dev/config/server-options.html#server-allowedhosts) option. For example, if the reverse proxy is sending requests to `http://vite:5173`, you need to add `vite` to the `server.allowedHosts` option.\n\n#### Accessing the development server via a domain other than `localhost` or `*.localhost`\nYou need to add the hostname to the new [`server.allowedHosts`](https://vite.dev/config/server-options.html#server-allowedhosts) option. For example, if you are accessing the development server via `http://foo.example.com:8080`, you need to add `foo.example.com` to the `server.allowedHosts` option.\n\n#### Using a plugin / framework that connects to the WebSocket server on their own from the browser\nIf you are using a plugin / framework, try upgrading to a newer version of Vite that fixes the vulnerability. If the WebSocket connection appears not to be working, the plugin / framework may have a code that connects to the WebSocket server on their own from the browser.\n\nIn that case, you can either:\n\n- fix the plugin / framework code to the make it compatible with the new version of Vite\n- set `legacy.skipWebSocketTokenCheck: true` to opt-out the fix for [2] while the plugin / framework is incompatible with the new version of Vite\n  - When enabling this option, **make sure that you are aware of the security implications** described in the impact section of [2] above.\n\n### Mitigation without upgrading Vite\n#### [1]: Permissive default CORS settings\nSet `server.cors` to `false` or limit `server.cors.origin` to trusted origins.\n\n#### [2]: Lack of validation on the Origin header for WebSocket connections\nThere aren\u0027t any mitigations for this.\n\n#### [3]: Lack of validation on the Host header for HTTP requests\nUse Chrome 94+ or use HTTPS for the development server.\n\n### Details\n\nThere are three causes that allowed malicious websites to send any requests to the development server:\n\n#### [1]: Permissive default CORS settings\n\nVite sets the [`Access-Control-Allow-Origin`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin) header depending on [`server.cors`](https://vite.dev/config/server-options.html#server-cors) option. The default value was `true` which sets `Access-Control-Allow-Origin: *`. This allows websites on any origin to `fetch` contents served on the development server.\n\nAttack scenario:\n\n1. The attacker serves a malicious web page (`http://malicious.example.com`).\n2. The user accesses the malicious web page.\n3. The attacker sends a `fetch(\u0027http://127.0.0.1:5173/main.js\u0027)` request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that\u0027s not the case for the reasons above.\n4. The attacker gets the content of `http://127.0.0.1:5173/main.js`.\n\n#### [2]: Lack of validation on the Origin header for WebSocket connections\n\nVite starts a WebSocket server to handle HMR and other functionalities. This WebSocket server [did not perform validation on the Origin header](https://github.com/vitejs/vite/blob/v6.0.7/packages/vite/src/node/server/ws.ts#L145-L157) and was vulnerable to Cross-Site WebSocket Hijacking (CSWSH) attacks. With that attack, an attacker can read and write messages on the WebSocket connection. Vite only sends some information over the WebSocket connection ([list of the file paths that changed, the file content where the errored happened, etc.](https://github.com/vitejs/vite/blob/v6.0.7/packages/vite/types/hmrPayload.d.ts#L12-L72)), but plugins can send arbitrary messages and may include more sensitive information.\n\nAttack scenario:\n\n1. The attacker serves a malicious web page (`http://malicious.example.com`).\n2. The user accesses the malicious web page.\n3. The attacker runs `new WebSocket(\u0027http://127.0.0.1:5173\u0027, \u0027vite-hmr\u0027)` by JS in that malicious web page.\n4. The user edits some files.\n5. Vite sends some HMR messages over WebSocket.\n6. The attacker gets the content of the HMR messages.\n\n#### [3]: Lack of validation on the Host header for HTTP requests\n\nUnless [`server.https`](https://vite.dev/config/server-options.html#server-https) is set, Vite starts the development server on HTTP. Non-HTTPS servers are vulnerable to DNS rebinding attacks without validation on the Host header. But Vite did not perform validation on the Host header. By exploiting this vulnerability, an attacker can send arbitrary requests to the development server bypassing the same-origin policy.\n\n1. The attacker serves a malicious web page that is served on **HTTP** (`http://malicious.example.com:5173`) (HTTPS won\u0027t work).\n2. The user accesses the malicious web page.\n3. The attacker changes the DNS to point to 127.0.0.1 (or other private addresses).\n4. The attacker sends a `fetch(\u0027/main.js\u0027)` request by JS in that malicious web page.\n5. The attacker gets the content of `http://127.0.0.1:5173/main.js` bypassing the same origin policy.\n\n### Impact\n#### [1]: Permissive default CORS settings\nUsers with the default `server.cors` option may:\n\n- get the source code stolen by malicious websites\n- give the attacker access to functionalities that are not supposed to be exposed externally\n  - Vite core does not have any functionality that causes changes somewhere else when receiving a request, but plugins may implement those functionalities and servers behind `server.proxy` may have those functionalities.\n\n#### [2]: Lack of validation on the Origin header for WebSocket connections\nAll users may get the file paths of the files that changed and the file content where the error happened be stolen by malicious websites.\n\nFor users that is using a plugin that sends messages over WebSocket, that content may be stolen by malicious websites.\n\nFor users that is using a plugin that has a functionality that is triggered by messages over WebSocket, that functionality may be exploited by malicious websites.\n\n#### [3]: Lack of validation on the Host header for HTTP requests\nUsers using HTTP for the development server and using a browser that is not Chrome 94+ may:\n\n- get the source code stolen by malicious websites\n- give the attacker access to functionalities that are not supposed to be exposed externally\n  - Vite core does not have any functionality that causes changes somewhere else when receiving a request, but plugins may implement those functionalities and servers behind `server.proxy` may have those functionalities.\n\nChrome 94+ users are not affected for [3], because [sending a request to a private network page from public non-HTTPS page is forbidden](https://developer.chrome.com/blog/private-network-access-update#chrome_94) since Chrome 94.\n\n### Related Information\nSafari has [a bug that blocks requests to loopback addresses from HTTPS origins](https://bugs.webkit.org/show_bug.cgi?id=171934). This means when the user is using Safari and Vite is listening on lookback addresses, there\u0027s another condition of \"the malicious web page is served on HTTP\" to make [1] and [2] to work.\n\n### PoC\n#### [2]: Lack of validation on the Origin header for WebSocket connections\n1. I used the `react` template which utilizes HMR functionality.\n\n```\nnpm create vite@latest my-vue-app-react -- --template react\n```\n\n2. Then on a malicious server, serve the following POC html:\n```html\n\u003c!doctype html\u003e\n\u003chtml lang=\"en\"\u003e\n    \u003chead\u003e\n        \u003cmeta charset=\"utf-8\" /\u003e\n        \u003ctitle\u003evite CSWSH\u003c/title\u003e\n    \u003c/head\u003e\n    \u003cbody\u003e\n        \u003cdiv id=\"logs\"\u003e\u003c/div\u003e\n        \u003cscript\u003e\n            const div = document.querySelectorAll(\u0027#logs\u0027)[0];\n            const ws = new WebSocket(\u0027ws://localhost:5173\u0027,\u0027vite-hmr\u0027);\n            ws.onmessage = event =\u003e {\n                const logLine = document.createElement(\u0027p\u0027);\n                logLine.innerHTML = event.data;\n                div.append(logLine);\n            };\n        \u003c/script\u003e\n    \u003c/body\u003e\n\u003c/html\u003e\n```\n\n3. Kick off Vite \n\n```\nnpm run dev\n```\n\n4. Load the development server (open `http://localhost:5173/`) as well as the malicious page in the browser. \n5. Edit `src/App.jsx` file and intentionally place a syntax error\n6. Notice how the malicious page can view the websocket messages and a snippet of the source code is exposed\n\nHere\u0027s a video demonstrating the POC:\n\nhttps://github.com/user-attachments/assets/a4ad05cd-0b34-461c-9ff6-d7c8663d6961",
  "id": "GHSA-vg6x-rcgg-rjx6",
  "modified": "2025-02-07T17:38:57Z",
  "published": "2025-01-21T19:52:55Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vitejs/vite/security/advisories/GHSA-vg6x-rcgg-rjx6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-24010"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vitejs/vite"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Websites were able to send any requests to the development server and read the response in vite"
}

GHSA-VJ7Q-GJH5-988W

Vulnerability from github – Published: 2026-07-16 20:14 – Updated: 2026-07-16 20:14

Summary

MCP Python SDK: WebSocket server transport does not support Host/Origin validation

Details

Summary

In affected versions, the deprecated WebSocket server transport (mcp.server.websocket.websocket_server) accepted the WebSocket handshake without applying any Host or Origin header validation. The TransportSecuritySettings mechanism that the SSE and Streamable HTTP transports use for this purpose was not wired into the WebSocket transport, so there was no SDK-level way to restrict which origins could connect.

Am I affected?

Only if a developer's application server exposes mcp.server.websocket.websocket_server. This transport has never been part of the MCP specification, is marked deprecated, and is not reachable through FastMCP — a developer must have wired it into an ASGI application themselves. Servers using stdio, SSE, or Streamable HTTP are not affected by this advisory.

Details

websocket_server() constructed a Starlette WebSocket and called accept(subprotocol="mcp") immediately, with no inspection of the connection's headers. By contrast, SseServerTransport and StreamableHTTPServerTransport accept an optional security_settings: TransportSecuritySettings and run TransportSecurityMiddleware.validate_request() against the incoming Host and Origin headers before establishing a session. Because browsers attach an Origin header to cross-origin WebSocket upgrade requests but do not enforce a same-origin policy on the response, a web page served from any origin could open a WebSocket to a reachable MCP server on this transport, complete the initialize handshake, and issue JSON-RPC requests on the resulting session.

Impact

A user who runs an MCP server on this transport bound to localhost or a LAN address, without a separate authentication or origin gate in front of it, and visits a malicious web page, can have that page enumerate and invoke the server's tools and read its resources. The consequences depend entirely on what the server exposes. The transport itself requires no token or prior session. Some browsers prompt before allowing a public page to open a connection to a local-network address, which adds a user-interaction step but is not a substitute for server-side validation.

Mitigation

Upgrade to version 1.28.1 or later, in which websocket_server() accepts the same optional security_settings: TransportSecuritySettings argument as the other HTTP-based transports and validates the Host and Origin headers before accepting the handshake; a request that fails validation is rejected with HTTP 403 and ValueError("Request validation failed") is raised to the caller. As with the other transports the parameter defaults to None, which leaves validation disabled, so upgrading alone does not change behaviour: pass a TransportSecuritySettings with enable_dns_rebinding_protection=True and appropriate allowed_hosts / allowed_origins to receive the protection. The recommended path remains to migrate off this deprecated transport to Streamable HTTP, where FastMCP enables this protection automatically for localhost binds. The WebSocket transport has been removed entirely in v2.

Severity

7.6 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "mcp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.28.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-59950"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1385",
      "CWE-346"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-16T20:14:34Z",
    "nvd_published_at": "2026-07-15T21:16:55Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nIn affected versions, the deprecated WebSocket server transport (`mcp.server.websocket.websocket_server`) accepted the WebSocket handshake without applying any `Host` or `Origin` header validation. The `TransportSecuritySettings` mechanism that the SSE and Streamable HTTP transports use for this purpose was not wired into the WebSocket transport, so there was no SDK-level way to restrict which origins could connect.\n\n### Am I affected?\nOnly if a developer\u0027s application server exposes `mcp.server.websocket.websocket_server`. This transport has never been part of the MCP specification, is marked deprecated, and is not reachable through `FastMCP` \u2014 a developer must have wired it into an ASGI application themselves. Servers using stdio, SSE, or Streamable HTTP are not affected by this advisory.\n\n### Details\n`websocket_server()` constructed a Starlette `WebSocket` and called `accept(subprotocol=\"mcp\")` immediately, with no inspection of the connection\u0027s headers. By contrast, `SseServerTransport` and `StreamableHTTPServerTransport` accept an optional `security_settings: TransportSecuritySettings` and run `TransportSecurityMiddleware.validate_request()` against the incoming `Host` and `Origin` headers before establishing a session. Because browsers attach an `Origin` header to cross-origin WebSocket upgrade requests but do not enforce a same-origin policy on the response, a web page served from any origin could open a WebSocket to a reachable MCP server on this transport, complete the `initialize` handshake, and issue JSON-RPC requests on the resulting session.\n\n### Impact\nA user who runs an MCP server on this transport bound to localhost or a LAN address, without a separate authentication or origin gate in front of it, and visits a malicious web page, can have that page enumerate and invoke the server\u0027s tools and read its resources. The consequences depend entirely on what the server exposes. The transport itself requires no token or prior session. Some browsers prompt before allowing a public page to open a connection to a local-network address, which adds a user-interaction step but is not a substitute for server-side validation.\n\n### Mitigation\nUpgrade to version 1.28.1 or later, in which `websocket_server()` accepts the same optional `security_settings: TransportSecuritySettings` argument as the other HTTP-based transports and validates the `Host` and `Origin` headers before accepting the handshake; a request that fails validation is rejected with HTTP 403 and `ValueError(\"Request validation failed\")` is raised to the caller. As with the other transports the parameter defaults to `None`, which leaves validation disabled, so upgrading alone does not change behaviour: pass a `TransportSecuritySettings` with `enable_dns_rebinding_protection=True` and appropriate `allowed_hosts` / `allowed_origins` to receive the protection. The recommended path remains to migrate off this deprecated transport to Streamable HTTP, where `FastMCP` enables this protection automatically for localhost binds. The WebSocket transport has been removed entirely in v2.",
  "id": "GHSA-vj7q-gjh5-988w",
  "modified": "2026-07-16T20:14:34Z",
  "published": "2026-07-16T20:14:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-vj7q-gjh5-988w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59950"
    },
    {
      "type": "WEB",
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/2992"
    },
    {
      "type": "WEB",
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/777b8d06710c140e3606b0d4598e2aa48546c266"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/modelcontextprotocol/python-sdk"
    },
    {
      "type": "WEB",
      "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.28.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MCP Python SDK: WebSocket server transport does not support Host/Origin validation"
}

GHSA-XG8J-J6VP-6H5W

Vulnerability from github – Published: 2025-08-03 12:30 – Updated: 2025-11-05 20:34

Summary

Apache Zeppelin: Missing Origin Validation in WebSockets vulnerability

Details

Missing Origin Validation in WebSockets vulnerability in Apache Zeppelin.

The attacker could access the Zeppelin server from another origin without any restriction, and get internal information about paragraphs. This issue affects Apache Zeppelin: from 0.11.1 before 0.12.0.

Users are recommended to upgrade to version 0.12.0, which fixes the issue.

Severity

6.9 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.apache.zeppelin:zeppelin-shell"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.11.1"
            },
            {
              "fixed": "0.12.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-51775"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1385"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-08-04T16:39:35Z",
    "nvd_published_at": "2025-08-03T11:15:26Z",
    "severity": "MODERATE"
  },
  "details": "Missing Origin Validation in WebSockets vulnerability in Apache Zeppelin.\n\nThe attacker could access the Zeppelin server from another origin without any restriction, and get internal information about paragraphs.\u00a0\nThis issue affects Apache Zeppelin: from 0.11.1 before 0.12.0.\n\nUsers are recommended to upgrade to version 0.12.0, which fixes the issue.",
  "id": "GHSA-xg8j-j6vp-6h5w",
  "modified": "2025-11-05T20:34:05Z",
  "published": "2025-08-03T12:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-51775"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apache/zeppelin/pull/4823"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/apache/zeppelin"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2025/08/03/5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Apache Zeppelin: Missing Origin Validation in WebSockets vulnerability"
}

Mitigation

Implementation

Enable CORS-like access restrictions by verifying the 'Origin' header during the WebSocket handshake.

Mitigation

Implementation

Use a randomized CSRF token to verify requests.

Mitigation

Implementation

Use TLS to securely communicate using 'wss' (WebSocket Secure) instead of 'ws'.

Mitigation

Architecture and Design Implementation

Require user authentication prior to the WebSocket connection being established. For example, the WS library in Node has a 'verifyClient' function.

Mitigation

Implementation

Leverage rate limiting to prevent against DoS. Use of the leaky bucket algorithm can help with this.

Mitigation

Implementation

Use a library that provides restriction of the payload size. For example, WS library for Node includes 'maxPayloadoption' that can be set.

Mitigation

Implementation

Treat data/input as untrusted in both directions and apply the same data/input sanitization as XSS, SQLi, etc.

No CAPEC attack patterns related to this CWE.

← Back to the CWE list

CWE-1385

Missing Origin Validation in WebSockets

GHSA-VG6X-RCGG-RJX6

Summary

Upgrade Path

Using the backend integration feature

Using a reverse proxy in front of Vite

Accessing the development server via a domain other than localhost or *.localhost

Using a plugin / framework that connects to the WebSocket server on their own from the browser

Mitigation without upgrading Vite

[1]: Permissive default CORS settings

[2]: Lack of validation on the Origin header for WebSocket connections

[3]: Lack of validation on the Host header for HTTP requests

Details

[1]: Permissive default CORS settings

[2]: Lack of validation on the Origin header for WebSocket connections

[3]: Lack of validation on the Host header for HTTP requests

Impact

[1]: Permissive default CORS settings

[2]: Lack of validation on the Origin header for WebSocket connections

[3]: Lack of validation on the Host header for HTTP requests

Related Information

PoC

[2]: Lack of validation on the Origin header for WebSocket connections

GHSA-VJ7Q-GJH5-988W

Summary

Am I affected?

Details

Impact

Mitigation

GHSA-XG8J-J6VP-6H5W

Mitigation

Mitigation

Mitigation

Mitigation

Mitigation

Mitigation

Mitigation

Accessing the development server via a domain other than `localhost` or `*.localhost`