diff --git a/lib/request.js b/lib/request.js
index c1cd37e8..ec004ab1 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -75,7 +75,13 @@ class Request {
    * @return {boolean}
    */
   is(...types) {
-    return typeis(this, types.flat()) || false;
+    try {
+      return typeis(this, types.flat()) || false;
+    } catch {
+      // type-is throws on some malformed content-types (e.g. `;charset=utf-8`),
+      // which can never match any of the given mime types.
+      return false;
+    }
   }
 }
 
diff --git a/test/integration/handlers/authenticate-handler_test.js b/test/integration/handlers/authenticate-handler_test.js
index f3e5e92d..a28a35da 100644
--- a/test/integration/handlers/authenticate-handler_test.js
+++ b/test/integration/handlers/authenticate-handler_test.js
@@ -525,6 +525,27 @@ describe('AuthenticateHandler integration', function () {
       }
     });
 
+    it('should throw an error if the media type is malformed', async function () {
+      const handler = new AuthenticateHandler({
+        model: { getAccessToken: function () {} },
+      });
+      const request = new Request({
+        body: { access_token: 'foo' },
+        headers: { 'content-type': ';charset=utf-8', 'transfer-encoding': 'chunked' },
+        method: 'POST',
+        query: {},
+      });
+
+      try {
+        await handler.getTokenFromRequestBody(request);
+
+        should.fail();
+      } catch (e) {
+        e.should.be.an.instanceOf(InvalidRequestError);
+        e.message.should.equal('Invalid request: content must be application/x-www-form-urlencoded');
+      }
+    });
+
     it('should return the bearer token', function () {
       const handler = new AuthenticateHandler({
         model: { getAccessToken: function () {} },
diff --git a/test/integration/handlers/token-handler_test.js b/test/integration/handlers/token-handler_test.js
index 4fc52ca0..4df497c4 100644
--- a/test/integration/handlers/token-handler_test.js
+++ b/test/integration/handlers/token-handler_test.js
@@ -286,6 +286,33 @@ describe('TokenHandler integration', function () {
         });
     });
 
+    it('should throw an error if the media type is malformed', function () {
+      const model = Model.from({
+        getClient: function () {},
+        saveToken: function () {},
+      });
+      const handler = new TokenHandler({
+        accessTokenLifetime: 120,
+        model: model,
+        refreshTokenLifetime: 120,
+      });
+      const request = new Request({
+        body: { grant_type: 'password' },
+        headers: { 'content-type': ';charset=utf-8', 'transfer-encoding': 'chunked' },
+        method: 'POST',
+        query: {},
+      });
+      const response = new Response({ body: {}, headers: {} });
+
+      return handler
+        .handle(request, response)
+        .then(should.fail)
+        .catch(function (e) {
+          e.should.be.an.instanceOf(InvalidRequestError);
+          e.message.should.equal('Invalid request: content must be application/x-www-form-urlencoded');
+        });
+    });
+
     it('should throw the error if an oauth error is thrown', function () {
       const model = Model.from({
         getClient: function () {},
diff --git a/test/integration/request_test.js b/test/integration/request_test.js
index 7766603f..83dae562 100644
--- a/test/integration/request_test.js
+++ b/test/integration/request_test.js
@@ -175,6 +175,20 @@ describe('Request integration', function () {
       request.is('json').should.be.false;
     });
 
+    it('should return `false` if the content type is malformed', function () {
+      const request = new Request({
+        body: {},
+        headers: {
+          'content-type': ';charset=utf-8',
+          'transfer-encoding': 'chunked',
+        },
+        method: {},
+        query: {},
+      });
+
+      request.is('application/x-www-form-urlencoded').should.be.false;
+    });
+
     it('should return `false` if the request has no body', function () {
       const request = new Request({
         body: {},