diff --git a/backend/open_webui/routers/images.py b/backend/open_webui/routers/images.py
index 1c6c240d5d..5bfb89357b 100644
--- a/backend/open_webui/routers/images.py
+++ b/backend/open_webui/routers/images.py
@@ -433,7 +433,7 @@ async def get_image_data(data: str, headers=None, trusted_base_url: str | None =
             if trusted_base_url and _is_same_origin(data, trusted_base_url):
                 log.debug(f'Skipping URL validation for trusted backend: {data}')
             else:
-                validate_url(data)
+                await asyncio.to_thread(validate_url, data)
             session = await get_session()
             async with session.get(
                 data,
@@ -862,7 +862,7 @@ async def image_edits(
                 # called only on the originally-submitted URL; following 3xx redirects
                 # without re-validation would let an attacker reach private IPs via a
                 # public host that redirects internally (e.g. cloud-metadata exfil).
-                validate_url(data)
+                await asyncio.to_thread(validate_url, data)
                 # SSRF-safe session: re-checks the connect-time IP so a rebinding DNS answer
                 # that passed validate_url cannot reach an internal address.
                 async with get_ssrf_safe_session() as session:
diff --git a/backend/open_webui/utils/files.py b/backend/open_webui/utils/files.py
index b91350ca4b..e43057c5d8 100644
--- a/backend/open_webui/utils/files.py
+++ b/backend/open_webui/utils/files.py
@@ -58,7 +58,7 @@ async def get_image_base64_from_url(url: str, user=None) -> Optional[str]:
             # called only on the originally-submitted URL; following 3xx redirects
             # without re-validation would let an attacker reach private IPs via a
             # public host that redirects internally (e.g. cloud-metadata exfil).
-            validate_url(url)
+            await asyncio.to_thread(validate_url, url)
             # Fetch through an SSRF-safe session that re-checks the connect-time IP, so a
             # rebinding DNS answer that passed validate_url cannot reach an internal address.
             async with get_ssrf_safe_session() as session:
diff --git a/backend/open_webui/utils/oauth.py b/backend/open_webui/utils/oauth.py
index 4049980702..2ffb209689 100644
--- a/backend/open_webui/utils/oauth.py
+++ b/backend/open_webui/utils/oauth.py
@@ -1,3 +1,4 @@
+import asyncio
 import base64
 import fnmatch
 import hashlib
@@ -1603,7 +1604,7 @@ class OAuthManager:
             return '/user.png'
 
         try:
-            validate_url(picture_url)
+            await asyncio.to_thread(validate_url, picture_url)
 
             get_kwargs = {}
             if access_token:
diff --git a/backend/open_webui/utils/webhook.py b/backend/open_webui/utils/webhook.py
index 5fc6440c07..1c3bfd22ba 100644
--- a/backend/open_webui/utils/webhook.py
+++ b/backend/open_webui/utils/webhook.py
@@ -1,3 +1,4 @@
+import asyncio
 import json
 import logging
 
@@ -31,10 +32,10 @@ async def post_webhook(
 ) -> bool:
     try:
         log.debug(f'post_webhook: {url}, {message}, {event_data}')
-        # Block private-IP / loopback / cloud-metadata targets for every
-        # webhook source, including admin-managed event webhooks and
-        # user-configured notification URLs.
-        validate_url(url)
+        # Block private-IP / loopback / cloud-metadata targets — the URL is
+        # caller-controlled (user notification settings under
+        # ENABLE_USER_WEBHOOKS, automation notification triggers).
+        await asyncio.to_thread(validate_url, url)
         payload = {}
 
         # Slack and Google Chat Webhooks