diff --git a/web/webhook.go b/web/webhook.go
index 1e33b367d3..cf000160a2 100644
--- a/web/webhook.go
+++ b/web/webhook.go
@@ -5,6 +5,7 @@ package web
 
 import (
 	"io"
+	"mime"
 	"net/http"
 	"strings"
 
@@ -28,7 +29,11 @@ func incomingWebhook(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	var err *model.AppError
 	incomingWebhookPayload := &model.IncomingWebhookRequest{}
-	contentType := r.Header.Get("Content-Type")
+	mediaType, _, mimeErr := mime.ParseMediaType(r.Header.Get("Content-Type"))
+	if mimeErr != nil && mimeErr != mime.ErrInvalidMediaParameter {
+		c.Err = model.NewAppError("incomingWebhook", "api.webhook.incoming.error", nil, mimeErr.Error(), http.StatusBadRequest)
+		return
+	}
 
 	defer func() {
 		if *c.App.Config().LogSettings.EnableWebhookDebugging {
@@ -38,7 +43,7 @@ func incomingWebhook(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}()
 
-	if strings.Split(contentType, "; ")[0] == "application/x-www-form-urlencoded" {
+	if mediaType == "application/x-www-form-urlencoded" {
 		payload := strings.NewReader(r.FormValue("payload"))
 
 		incomingWebhookPayload, err = decodePayload(payload)
@@ -46,7 +51,7 @@ func incomingWebhook(c *Context, w http.ResponseWriter, r *http.Request) {
 			c.Err = err
 			return
 		}
-	} else if strings.HasPrefix(contentType, "multipart/form-data") {
+	} else if mediaType == "multipart/form-data" {
 		r.ParseMultipartForm(0)
 
 		decoder := schema.NewDecoder()
diff --git a/web/webhook_test.go b/web/webhook_test.go
index 47a7e88d16..1e918cf24b 100644
--- a/web/webhook_test.go
+++ b/web/webhook_test.go
@@ -87,14 +87,42 @@ func TestIncomingWebhook(t *testing.T) {
 		assert.Nil(t, err)
 		assert.True(t, resp.StatusCode == http.StatusOK)
 
+		resp, err = http.Post(url, "AppLicaTion/x-www-Form-urlencoded", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusOK)
+
+		resp, err = http.Post(url, "application/x-www-form-urlencoded;charset=utf-8", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusOK)
+
+		resp, err = http.Post(url, "application/x-www-form-urlencoded; charset=utf-8", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusOK)
+
+		resp, err = http.Post(url, "application/x-www-form-urlencoded wrongtext", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusBadRequest)
+
 		resp, err = http.Post(url, "application/json", strings.NewReader("{\"text\":\""+tooLongText+"\"}"))
 		require.Nil(t, err)
 		assert.True(t, resp.StatusCode == http.StatusOK)
 
+		resp, err = http.Post(url, "application/x-www-form-urlencoded", strings.NewReader("{\"text\":\""+tooLongText+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusBadRequest)
+
+		resp, err = http.Post(url, "application/json", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusBadRequest)
+
 		payloadMultiPart := "------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"username\"\r\n\r\nwebhook-bot\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"text\"\r\n\r\nthis is a test :tada:\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW--"
 		resp, err = http.Post(ApiClient.Url+"/hooks/"+hook.Id, "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW", strings.NewReader(payloadMultiPart))
 		require.Nil(t, err)
 		assert.True(t, resp.StatusCode == http.StatusOK)
+
+		resp, err = http.Post(url, "mimetype/wrong", strings.NewReader("payload={\"text\":\""+text+"\"}"))
+		assert.Nil(t, err)
+		assert.True(t, resp.StatusCode == http.StatusBadRequest)
 	})
 
 	t.Run("WebhookExperimentalReadOnly", func(t *testing.T) {