fix:image url validation and signout post (open-webui#24420)

* refac(routers): reject external URLs in profile/model image handlers

* refac(ui): centralize image URL validation in safeImageUrl helper

* refac(auths): make signout POST-only

* refac: gate external profile image redirect behind ENABLE_PROFILE_IMAGE_URL_FORWARDING

Restore the 302 redirect for external http(s) profile image URLs in
the user and model profile-image endpoints, but gate it behind a new
ENABLE_PROFILE_IMAGE_URL_FORWARDING env flag (default: True).

Existing deployments that rely on external profile image forwarding
continue to work unchanged.  Operators who want to suppress the
redirect (to prevent client-side IP/UA/Referer leaks) can set the
flag to False.

Author: Classic298

backend/open_webui/env.py

@@ -249,6 +249,19 @@ def parse_section(section):
 
 ENABLE_EASTER_EGGS = os.environ.get('ENABLE_EASTER_EGGS', 'True').lower() == 'true'
 
+####################################
+# ENABLE_PROFILE_IMAGE_URL_FORWARDING
+####################################
+
+# When True (default), the user and model profile-image endpoints
+# honour external http(s) URLs stored in profile_image_url by issuing a
+# 302 redirect to the original origin.  Set to False to suppress the
+# redirect (prevents client-side IP/UA/Referer leaks to attacker-
+# controlled origins) and fall through to the default image instead.
+ENABLE_PROFILE_IMAGE_URL_FORWARDING = os.environ.get(
+    'ENABLE_PROFILE_IMAGE_URL_FORWARDING', 'True'
+).lower() == 'true'
+
 ####################################
 # WEBUI_BUILD_HASH
 ####################################

backend/open_webui/routers/auths.py

@@ -785,7 +785,7 @@ async def signup(
         raise HTTPException(500, detail='An internal error occurred during signup.')
 
 
-@router.get('/signout')
+@router.post('/signout')
 async def signout(request: Request, response: Response, db: AsyncSession = Depends(get_async_session)):
     # get auth token from headers or cookies
     token = None

backend/open_webui/routers/models.py

@@ -28,15 +28,16 @@
     Depends,
     HTTPException,
     Request,
-    status,
     Response,
+    status,
 )
 from fastapi.responses import RedirectResponse, StreamingResponse
 
 
 from open_webui.utils.auth import get_admin_user, get_verified_user
 from open_webui.utils.access_control import has_permission, filter_allowed_access_grants
 from open_webui.config import BYPASS_ADMIN_ACCESS_CONTROL
+from open_webui.env import ENABLE_PROFILE_IMAGE_URL_FORWARDING
 from open_webui.internal.db import get_async_session
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -484,10 +485,14 @@ async def get_model_profile_image(
 
     if profile_image_url:
         if profile_image_url.startswith('http'):
-            return Response(
-                status_code=status.HTTP_302_FOUND,
-                headers={'Location': profile_image_url},
-            )
+            if ENABLE_PROFILE_IMAGE_URL_FORWARDING:
+                return Response(
+                    status_code=status.HTTP_302_FOUND,
+                    headers={'Location': profile_image_url},
+                )
+            # When forwarding is disabled, fall through to the
+            # default image to prevent client-side IP/UA/Referer
+            # leaks via 302 redirect to external origins.
         elif profile_image_url.startswith('data:image'):
             try:
                 header, base64_data = profile_image_url.split(',', 1)

backend/open_webui/routers/users.py

@@ -29,7 +29,7 @@
 )
 
 from open_webui.constants import ERROR_MESSAGES
-from open_webui.env import STATIC_DIR
+from open_webui.env import ENABLE_PROFILE_IMAGE_URL_FORWARDING, STATIC_DIR
 from open_webui.internal.db import get_async_session
 
 
@@ -478,12 +478,15 @@ async def get_user_profile_image_by_id(user_id: str, user=Depends(get_verified_u
     user = await Users.get_user_by_id(user_id)
     if user:
         if user.profile_image_url:
-            # check if it's url or base64
             if user.profile_image_url.startswith('http'):
-                return Response(
-                    status_code=status.HTTP_302_FOUND,
-                    headers={'Location': user.profile_image_url},
-                )
+                if ENABLE_PROFILE_IMAGE_URL_FORWARDING:
+                    return Response(
+                        status_code=status.HTTP_302_FOUND,
+                        headers={'Location': user.profile_image_url},
+                    )
+                # When forwarding is disabled, fall through to the
+                # default image to prevent client-side IP/UA/Referer
+                # leaks via 302 redirect to external origins.
             elif user.profile_image_url.startswith('data:image'):
                 try:
                     header, base64_data = user.profile_image_url.split(',', 1)

src/lib/apis/auths/index.ts

@@ -328,7 +328,7 @@ export const userSignOut = async () => {
 	let error = null;
 
 	const res = await fetch(`${WEBUI_API_BASE_URL}/auths/signout`, {
-		method: 'GET',
+		method: 'POST',
 		headers: {
 			'Content-Type': 'application/json'
 		},

src/lib/components/chat/Messages/ProfileImage.svelte

@@ -1,20 +1,14 @@
 <script lang="ts">
 	import { WEBUI_BASE_URL } from '$lib/constants';
+	import { safeImageUrl } from '$lib/utils/safeImageUrl';
 
 	export let className = 'size-8';
 	export let src = `${WEBUI_BASE_URL}/static/favicon.png`;
 </script>
 
 <img
 	aria-hidden="true"
-	src={src === ''
-		? `${WEBUI_BASE_URL}/static/favicon.png`
-		: src.startsWith(WEBUI_BASE_URL) ||
-			  src.startsWith('https://www.gravatar.com/avatar/') ||
-			  src.startsWith('data:') ||
-			  src.startsWith('/')
-			? src
-			: `${WEBUI_BASE_URL}/user.png`}
+	src={safeImageUrl(src)}
 	class=" {className} object-cover rounded-full"
 	alt="profile"
 	draggable="false"

src/lib/components/common/Image.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { WEBUI_BASE_URL } from '$lib/constants';
+	import { safeImageUrl } from '$lib/utils/safeImageUrl';
 
 	import { settings } from '$lib/stores';
 	import ImagePreview from './ImagePreview.svelte';
@@ -19,7 +20,7 @@
 	const i18n = getContext('i18n');
 
 	let _src = '';
-	$: _src = src.startsWith('/') ? `${WEBUI_BASE_URL}${src}` : src;
+	$: _src = safeImageUrl(src.startsWith('/') ? `${WEBUI_BASE_URL}${src}` : src);
 
 	let showImagePreview = false;
 </script>

src/lib/components/common/RichTextInput/Image/image.ts

@@ -1,4 +1,5 @@
 import { mergeAttributes, Node, nodeInputRule } from '@tiptap/core';
+import { safeImageUrl } from '$lib/utils/safeImageUrl';
 
 export interface ImageOptions {
 	/**
@@ -137,12 +138,12 @@ export const Image = Node.create<ImageOptions>({
 			if (editorFiles && node.attrs.src.startsWith('data://')) {
 				const file = editorFiles.find((f) => f.id === fileId);
 				if (file) {
-					img.setAttribute('src', file.url || '');
+					img.setAttribute('src', safeImageUrl(file.url || ''));
 				} else {
 					img.setAttribute('src', '/image-placeholder.png');
 				}
 			} else {
-				img.setAttribute('src', node.attrs.src || '');
+				img.setAttribute('src', safeImageUrl(node.attrs.src || ''));
 			}
 
 			img.setAttribute('alt', node.attrs.alt || '');
@@ -153,7 +154,7 @@ export const Image = Node.create<ImageOptions>({
 				if (files && node.attrs.src.startsWith('data://')) {
 					const file = editorFiles.find((f) => f.id === fileId);
 					if (file) {
-						img.setAttribute('src', file.url || '');
+						img.setAttribute('src', safeImageUrl(file.url || ''));
 					} else {
 						img.setAttribute('src', '/image-placeholder.png');
 					}

src/lib/utils/safeImageUrl.ts

@@ -0,0 +1,33 @@
+import { WEBUI_BASE_URL } from '$lib/constants';
+
+const PLACEHOLDER_IMAGE = '/favicon.png';
+
+/**
+ * Validates an image URL against an allowlist of safe patterns and returns
+ * the URL if trusted, or a placeholder otherwise.
+ *
+ * Allowed patterns:
+ *   - Relative paths (starting with '/')
+ *   - data:image/* URIs
+ *   - Same-origin URLs (starting with WEBUI_BASE_URL)
+ *   - Gravatar URLs (https://www.gravatar.com/avatar/)
+ *
+ * All other URLs (including arbitrary http(s):// origins) are rejected to
+ * prevent client-side IP/UA/Referer leaks to attacker-controlled servers.
+ */
+export function safeImageUrl(url: string): string {
+	if (!url || url === '') {
+		return `${WEBUI_BASE_URL}${PLACEHOLDER_IMAGE}`;
+	}
+
+	if (
+		url.startsWith(WEBUI_BASE_URL) ||
+		url.startsWith('https://www.gravatar.com/avatar/') ||
+		url.startsWith('data:') ||
+		url.startsWith('/')
+	) {
+		return url;
+	}
+
+	return `${WEBUI_BASE_URL}${PLACEHOLDER_IMAGE}`;
+}