diff --git a/pkg/models/webhooks_ssrf_test.go b/pkg/models/webhooks_ssrf_test.go
new file mode 100644
index 000000000..fda2dca75
--- /dev/null
+++ b/pkg/models/webhooks_ssrf_test.go
@@ -0,0 +1,145 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package models
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"code.vikunja.io/api/pkg/config"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestWebhookSSRFProtection(t *testing.T) {
+	// Reset the singleton client before each test
+	resetWebhookClient := func() {
+		webhookClient = nil
+	}
+
+	t.Run("blocks requests to loopback addresses", func(t *testing.T) {
+		resetWebhookClient()
+		config.WebhooksAllowNonRoutableIPs.Set(false)
+		config.WebhooksProxyURL.Set("")
+		config.WebhooksProxyPassword.Set("")
+
+		w := &Webhook{
+			ID:        1,
+			TargetURL: "http://127.0.0.1:12345/hook",
+		}
+
+		err := w.sendWebhookPayload(&WebhookPayload{
+			EventName: "test.event",
+		})
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "prohibited")
+	})
+
+	t.Run("allows requests to public addresses", func(t *testing.T) {
+		resetWebhookClient()
+		config.WebhooksAllowNonRoutableIPs.Set(false)
+		config.WebhooksProxyURL.Set("")
+		config.WebhooksProxyPassword.Set("")
+
+		// Start a test server (binds to 127.0.0.1 but we test
+		// separately that public IPs are allowed in principle)
+		ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusOK)
+		}))
+		defer ts.Close()
+
+		// When allownonroutableips is false, even our test server
+		// on 127.0.0.1 should be blocked. This confirms the guard works.
+		w := &Webhook{
+			ID:        1,
+			TargetURL: ts.URL + "/hook",
+		}
+
+		err := w.sendWebhookPayload(&WebhookPayload{
+			EventName: "test.event",
+		})
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "prohibited")
+	})
+
+	t.Run("allows loopback when allownonroutableips is true", func(t *testing.T) {
+		resetWebhookClient()
+		config.WebhooksAllowNonRoutableIPs.Set(true)
+		config.WebhooksProxyURL.Set("")
+		config.WebhooksProxyPassword.Set("")
+
+		ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusOK)
+		}))
+		defer ts.Close()
+
+		w := &Webhook{
+			ID:        1,
+			TargetURL: ts.URL + "/hook",
+		}
+
+		err := w.sendWebhookPayload(&WebhookPayload{
+			EventName: "test.event",
+		})
+		require.NoError(t, err)
+	})
+
+	t.Run("blocks requests to private RFC1918 addresses", func(t *testing.T) {
+		resetWebhookClient()
+		config.WebhooksAllowNonRoutableIPs.Set(false)
+		config.WebhooksProxyURL.Set("")
+		config.WebhooksProxyPassword.Set("")
+
+		privateAddrs := []string{
+			"http://10.0.0.1:80/hook",
+			"http://172.16.0.1:80/hook",
+			"http://192.168.1.1:80/hook",
+		}
+
+		for _, addr := range privateAddrs {
+			webhookClient = nil // reset singleton for each
+			w := &Webhook{
+				ID:        1,
+				TargetURL: addr,
+			}
+
+			err := w.sendWebhookPayload(&WebhookPayload{
+				EventName: "test.event",
+			})
+			require.Error(t, err, "expected SSRF block for %s", addr)
+		}
+	})
+
+	t.Run("blocks requests to metadata endpoint", func(t *testing.T) {
+		resetWebhookClient()
+		config.WebhooksAllowNonRoutableIPs.Set(false)
+		config.WebhooksProxyURL.Set("")
+		config.WebhooksProxyPassword.Set("")
+
+		w := &Webhook{
+			ID:        1,
+			TargetURL: "http://169.254.169.254/latest/meta-data/",
+		}
+
+		err := w.sendWebhookPayload(&WebhookPayload{
+			EventName: "test.event",
+		})
+		require.Error(t, err)
+	})
+}