JS: Add support for @vercel/node serverless functions

docs/codeql/reusables/supported-frameworks.rst

@@ -197,6 +197,7 @@ and the CodeQL library pack ``codeql/javascript-all`` (`changelog <https://githu
    superagent, Network communicator
    swig, templating language
    underscore, Utility library
+   vercel, Serverless framework
    vue, HTML framework
 
 

javascript/ql/lib/change-notes/2026-04-12-vercel-node.md

@@ -0,0 +1,4 @@
+---
+category: newFeature
+---
+* Added support for [`@vercel/node`](https://www.npmjs.com/package/@vercel/node) Vercel serverless functions. Handlers are recognised via the `VercelRequest`/`VercelResponse` TypeScript parameter types, and standard security queries (`js/reflected-xss`, `js/request-forgery`, `js/sql-injection`, `js/command-line-injection`, etc.) now detect vulnerabilities in Vercel API route files.

javascript/ql/lib/javascript.qll

@@ -134,6 +134,7 @@ import semmle.javascript.frameworks.TorrentLibraries
 import semmle.javascript.frameworks.Typeahead
 import semmle.javascript.frameworks.TrustedTypes
 import semmle.javascript.frameworks.UriLibraries
+import semmle.javascript.frameworks.VercelNode
 import semmle.javascript.frameworks.Vue
 import semmle.javascript.frameworks.Vuex
 import semmle.javascript.frameworks.Webix

javascript/ql/lib/semmle/javascript/frameworks/VercelNode.qll

@@ -0,0 +1,200 @@
+/**
+ * Provides classes for working with [@vercel/node](https://www.npmjs.com/package/@vercel/node) Vercel serverless functions.
+ */
+
+import javascript
+import semmle.javascript.frameworks.HTTP
+
+/**
+ * Provides classes for working with [@vercel/node](https://www.npmjs.com/package/@vercel/node) Vercel serverless functions.
+ *
+ * A Vercel serverless function is a module whose default export is a function
+ * with signature `(req: VercelRequest, res: VercelResponse) => void`, where
+ * the types are imported from the `@vercel/node` package. The Vercel runtime
+ * invokes the default export for every incoming HTTP request.
+ */
+module VercelNode {
+  /**
+   * A Vercel serverless function handler, identified as the default export of a
+   * module whose first two parameters are typed as `VercelRequest` and
+   * `VercelResponse` from `@vercel/node`.
+   *
+   * Since `@vercel/node` is commonly imported as a type-only import, handlers
+   * are recognised by their TypeScript parameter types. The default-export
+   * constraint excludes private helpers or test utilities that share the
+   * same signature.
+   */
+  class RouteHandler extends Http::Servers::StandardRouteHandler, DataFlow::FunctionNode {
+    DataFlow::ParameterNode req;
+    DataFlow::ParameterNode res;
+
+    RouteHandler() {
+      this = any(Module m).getAnExportedValue("default").getAFunctionValue() and
+      req = this.getParameter(0) and
+      res = this.getParameter(1) and
+      req.hasUnderlyingType("@vercel/node", "VercelRequest") and
+      res.hasUnderlyingType("@vercel/node", "VercelResponse")
+    }
+
+    /** Gets the parameter that contains the request object. */
+    DataFlow::ParameterNode getRequest() { result = req }
+
+    /** Gets the parameter that contains the response object. */
+    DataFlow::ParameterNode getResponse() { result = res }
+  }
+
+  /**
+   * A Vercel request source, that is, the request parameter of a route handler.
+   */
+  private class RequestSource extends Http::Servers::RequestSource {
+    RouteHandler rh;
+
+    RequestSource() { this = rh.getRequest() }
+
+    override RouteHandler getRouteHandler() { result = rh }
+  }
+
+  /**
+   * A Vercel response source, that is, the response parameter of a route handler.
+   */
+  private class ResponseSource extends Http::Servers::ResponseSource {
+    RouteHandler rh;
+
+    ResponseSource() { this = rh.getResponse() }
+
+    override RouteHandler getRouteHandler() { result = rh }
+  }
+
+  /**
+   * A chained response, such as `res.status(200)`, `res.type('html')`, or `res.set(...)`.
+   *
+   * These methods return the response object and are commonly chained before `send` or `json`.
+   */
+  private class ChainedResponseSource extends Http::Servers::ResponseSource {
+    RouteHandler rh;
+
+    ChainedResponseSource() {
+      exists(ResponseSource src |
+        this = src.ref().getAMethodCall(["status", "type", "set"]) and
+        rh = src.getRouteHandler()
+      )
+    }
+
+    override RouteHandler getRouteHandler() { result = rh }
+  }
+
+  /**
+   * An access to user-controlled input on a Vercel request.
+   *
+   * Covers `req.query`, `req.body`, `req.cookies`, and `req.url` (inherited
+   * from Node's `IncomingMessage`). Named-header accesses like `req.headers.host`
+   * are handled by `RequestHeaderAccess` below.
+   */
+  private class RequestInputAccess extends Http::RequestInputAccess {
+    RouteHandler rh;
+    string kind;
+
+    RequestInputAccess() {
+      exists(RequestSource src | rh = src.getRouteHandler() |
+        this = src.ref().getAPropertyRead("query") and kind = "parameter"
+        or
+        this = src.ref().getAPropertyRead("body") and kind = "body"
+        or
+        this = src.ref().getAPropertyRead("cookies") and kind = "cookie"
+        or
+        this = src.ref().getAPropertyRead("url") and kind = "url"
+      )
+      or
+      exists(RequestHeaderAccess access | this = access |
+        rh = access.getRouteHandler() and
+        kind = "header"
+      )
+    }
+
+    override RouteHandler getRouteHandler() { result = rh }
+
+    override string getKind() { result = kind }
+  }
+
+  /**
+   * An access to a named header on a Vercel request, for example
+   * `req.headers.host` or `req.headers.referer`.
+   */
+  private class RequestHeaderAccess extends Http::RequestHeaderAccess {
+    RouteHandler rh;
+
+    RequestHeaderAccess() {
+      exists(RequestSource src |
+        this = src.ref().getAPropertyRead("headers").getAPropertyRead() and
+        rh = src.getRouteHandler()
+      )
+    }
+
+    override string getAHeaderName() {
+      result = this.(DataFlow::PropRead).getPropertyName().toLowerCase()
+    }
+
+    override RouteHandler getRouteHandler() { result = rh }
+
+    override string getKind() { result = "header" }
+  }
+
+  /**
+   * An argument to `res.send(...)` on a Vercel response, including chained
+   * calls such as `res.status(200).send(...)`.
+   */
+  private class ResponseSendArgument extends Http::ResponseSendArgument {
+    RouteHandler rh;
+
+    ResponseSendArgument() {
+      exists(Http::Servers::ResponseSource src |
+        (src instanceof ResponseSource or src instanceof ChainedResponseSource) and
+        this = src.ref().getAMethodCall("send").getArgument(0) and
+        rh = src.getRouteHandler()
+      )
+    }
+
+    override RouteHandler getRouteHandler() { result = rh }
+  }
+
+  /**
+   * A call to `res.redirect(...)` on a Vercel response.
+   */
+  private class RedirectInvocation extends Http::RedirectInvocation, DataFlow::MethodCallNode {
+    RouteHandler rh;
+
+    RedirectInvocation() {
+      exists(ResponseSource src |
+        this = src.ref().getAMethodCall("redirect") and
+        rh = src.getRouteHandler()
+      )
+    }
+
+    override DataFlow::Node getUrlArgument() { result = this.getLastArgument() }
+
+    override RouteHandler getRouteHandler() { result = rh }
+  }
+
+  /**
+   * A call to `res.setHeader(name, value)` on a Vercel response.
+   */
+  private class SetHeader extends Http::ExplicitHeaderDefinition, DataFlow::CallNode {
+    RouteHandler rh;
+
+    SetHeader() {
+      exists(ResponseSource src |
+        this = src.ref().getAMethodCall("setHeader") and
+        rh = src.getRouteHandler()
+      )
+    }
+
+    override RouteHandler getRouteHandler() { result = rh }
+
+    override predicate definesHeaderValue(string headerName, DataFlow::Node headerValue) {
+      headerName = this.getArgument(0).getStringValue().toLowerCase() and
+      headerValue = this.getArgument(1)
+    }
+
+    override DataFlow::Node getNameNode() { result = this.getArgument(0) }
+  }
+}

javascript/ql/test/library-tests/frameworks/vercel/HeaderDefinition.qll

@@ -0,0 +1,7 @@
+import javascript
+
+query predicate test_HeaderDefinition(
+  Http::HeaderDefinition hd, string name, VercelNode::RouteHandler rh
+) {
+  hd.getRouteHandler() = rh and name = hd.getAHeaderName()
+}

javascript/ql/test/library-tests/frameworks/vercel/RedirectInvocation.qll

@@ -0,0 +1,7 @@
+import javascript
+
+query predicate test_RedirectInvocation(
+  Http::RedirectInvocation call, DataFlow::Node url, VercelNode::RouteHandler rh
+) {
+  call.getRouteHandler() = rh and url = call.getUrlArgument()
+}

javascript/ql/test/library-tests/frameworks/vercel/RequestInputAccess.qll

@@ -0,0 +1,7 @@
+import javascript
+
+query predicate test_RequestInputAccess(
+  Http::RequestInputAccess ria, string kind, VercelNode::RouteHandler rh
+) {
+  ria.getRouteHandler() = rh and kind = ria.getKind()
+}

javascript/ql/test/library-tests/frameworks/vercel/RequestSource.qll

@@ -0,0 +1,5 @@
+import javascript
+
+query predicate test_RequestSource(Http::Servers::RequestSource src, VercelNode::RouteHandler rh) {
+  src.getRouteHandler() = rh
+}

javascript/ql/test/library-tests/frameworks/vercel/ResponseSendArgument.qll

@@ -0,0 +1,7 @@
+import javascript
+
+query predicate test_ResponseSendArgument(
+  Http::ResponseSendArgument arg, VercelNode::RouteHandler rh
+) {
+  arg.getRouteHandler() = rh
+}

javascript/ql/test/library-tests/frameworks/vercel/ResponseSource.qll

@@ -0,0 +1,5 @@
+import javascript
+
+query predicate test_ResponseSource(Http::Servers::ResponseSource src, VercelNode::RouteHandler rh) {
+  src.getRouteHandler() = rh
+}

javascript/ql/test/library-tests/frameworks/vercel/RouteHandler.qll

@@ -0,0 +1,3 @@
+import javascript
+
+query predicate test_RouteHandler(VercelNode::RouteHandler rh) { any() }

javascript/ql/test/library-tests/frameworks/vercel/src/notahandler.ts

@@ -0,0 +1,8 @@
+import type { VercelRequest, VercelResponse } from "@vercel/node";
+
+// A default-exported function that has VercelRequest/VercelResponse at
+// positions 1 and 2, not 0 and 1. Vercel does not invoke it this way,
+// so it must NOT be recognised as a route handler.
+export default function notAHandler(ctx: unknown, req: VercelRequest, res: VercelResponse) {
+  res.send(req.query.name);
+}

javascript/ql/test/library-tests/frameworks/vercel/src/vercel.ts

@@ -0,0 +1,27 @@
+import type { VercelRequest, VercelResponse } from "@vercel/node";
+
+// A private helper with the same signature. Must NOT be recognised as a
+// route handler, since Vercel only invokes the default export.
+function internalHelper(req: VercelRequest, res: VercelResponse) {
+  res.send(req.query.name);
+}
+
+export default function handler(req: VercelRequest, res: VercelResponse) {
+  // Request inputs
+  const q = req.query;            // source: parameter
+  const b = req.body;              // source: body
+  const c = req.cookies;           // source: cookie
+  const u = req.url;               // source: url (inherited from IncomingMessage)
+  const host = req.headers.host;   // source: header (named)
+  const ref = req.headers.referer; // source: header (named)
+
+  // Response header definition
+  res.setHeader("Content-Type", "text/html");
+
+  // Response send (direct and chained)
+  res.send(q);
+  res.status(200).send(b);
+
+  // Redirect
+  res.redirect(req.query.url as string);
+}

javascript/ql/test/library-tests/frameworks/vercel/tests.expected

@@ -0,0 +1,22 @@
+test_RouteHandler
+| src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_RequestSource
+| src/vercel.ts:9:33:9:35 | req | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_ResponseSource
+| src/vercel.ts:9:53:9:55 | res | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:23:3:23:17 | res.status(200) | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_HeaderDefinition
+| src/vercel.ts:19:3:19:44 | res.set ... /html") | content-type | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_RedirectInvocation
+| src/vercel.ts:26:3:26:39 | res.red ... string) | src/vercel.ts:26:16:26:38 | req.que ...  string | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_RequestInputAccess
+| src/vercel.ts:11:13:11:21 | req.query | parameter | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:12:13:12:20 | req.body | body | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:13:13:13:23 | req.cookies | cookie | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:14:13:14:19 | req.url | url | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:15:16:15:31 | req.headers.host | header | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:16:15:16:33 | req.headers.referer | header | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:26:16:26:24 | req.query | parameter | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+test_ResponseSendArgument
+| src/vercel.ts:22:12:22:12 | q | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |
+| src/vercel.ts:23:24:23:24 | b | src/vercel.ts:9:16:27:1 | functio ... ing);\\n} |

javascript/ql/test/library-tests/frameworks/vercel/tests.ql

@@ -0,0 +1,7 @@
+import RouteHandler
+import RequestSource
+import ResponseSource
+import RequestInputAccess
+import HeaderDefinition
+import ResponseSendArgument
+import RedirectInvocation

javascript/ql/test/query-tests/Security/CWE-078/CommandInjection/CommandInjection.expected

@@ -110,6 +110,8 @@
 | promisification.js:151:28:151:31 | code | promisification.js:141:18:141:25 | req.body | promisification.js:151:28:151:31 | code | This command line depends on a $@. | promisification.js:141:18:141:25 | req.body | user-provided value |
 | promisification.js:152:25:152:28 | code | promisification.js:141:18:141:25 | req.body | promisification.js:152:25:152:28 | code | This command line depends on a $@. | promisification.js:141:18:141:25 | req.body | user-provided value |
 | third-party-command-injection.js:6:21:6:27 | command | third-party-command-injection.js:5:20:5:26 | command | third-party-command-injection.js:6:21:6:27 | command | This command line depends on a $@. | third-party-command-injection.js:5:20:5:26 | command | user-provided value |
+| vercel.ts:6:8:6:21 | "echo " + name | vercel.ts:5:16:5:24 | req.query | vercel.ts:6:8:6:21 | "echo " + name | This command line depends on a $@. | vercel.ts:5:16:5:24 | req.query | user-provided value |
+| vercel.ts:6:8:6:21 | "echo " + name | vercel.ts:5:16:5:29 | req.query.name | vercel.ts:6:8:6:21 | "echo " + name | This command line depends on a $@. | vercel.ts:5:16:5:29 | req.query.name | user-provided value |
 edges
 | actions.js:8:9:8:13 | title | actions.js:9:16:9:20 | title | provenance |  |
 | actions.js:8:17:8:57 | github. ... t.title | actions.js:8:9:8:13 | title | provenance |  |
@@ -340,6 +342,10 @@ edges
 | promisification.js:141:11:141:14 | code | promisification.js:152:25:152:28 | code | provenance |  |
 | promisification.js:141:18:141:25 | req.body | promisification.js:141:11:141:14 | code | provenance |  |
 | third-party-command-injection.js:5:20:5:26 | command | third-party-command-injection.js:6:21:6:27 | command | provenance |  |
+| vercel.ts:5:9:5:12 | name | vercel.ts:6:18:6:21 | name | provenance |  |
+| vercel.ts:5:16:5:24 | req.query | vercel.ts:5:9:5:12 | name | provenance |  |
+| vercel.ts:5:16:5:29 | req.query.name | vercel.ts:5:9:5:12 | name | provenance |  |
+| vercel.ts:6:18:6:21 | name | vercel.ts:6:8:6:21 | "echo " + name | provenance |  |
 nodes
 | actions.js:8:9:8:13 | title | semmle.label | title |
 | actions.js:8:17:8:57 | github. ... t.title | semmle.label | github. ... t.title |
@@ -591,6 +597,11 @@ nodes
 | promisification.js:152:25:152:28 | code | semmle.label | code |
 | third-party-command-injection.js:5:20:5:26 | command | semmle.label | command |
 | third-party-command-injection.js:6:21:6:27 | command | semmle.label | command |
+| vercel.ts:5:9:5:12 | name | semmle.label | name |
+| vercel.ts:5:16:5:24 | req.query | semmle.label | req.query |
+| vercel.ts:5:16:5:29 | req.query.name | semmle.label | req.query.name |
+| vercel.ts:6:8:6:21 | "echo " + name | semmle.label | "echo " + name |
+| vercel.ts:6:18:6:21 | name | semmle.label | name |
 subpaths
 | promisification.js:116:32:116:34 | cmd | promisification.js:118:21:118:23 | cmd | promisification.js:117:29:117:35 | resolve [Return] [resolve-value] | promisification.js:117:16:119:10 | new Pro ...      }) [PromiseValue] |
 | promisification.js:122:42:122:45 | code | promisification.js:116:32:116:34 | cmd | promisification.js:117:16:119:10 | new Pro ...      }) [PromiseValue] | promisification.js:122:24:122:46 | createE ... e(code) [PromiseValue] |

javascript/ql/test/query-tests/Security/CWE-078/CommandInjection/vercel.ts

@@ -0,0 +1,9 @@
+import type { VercelRequest, VercelResponse } from "@vercel/node";
+import { exec } from "child_process";
+
+export default function handler(req: VercelRequest, res: VercelResponse) {
+  const name = req.query.name as string; // $ Source
+  exec("echo " + name, (err, stdout) => { // $ Alert
+    res.send(stdout);
+  });
+}