Fix for aio-libs#5156

aiohttp/resolver.py

@@ -3,6 +3,7 @@
 
 from .abc import AbstractResolver
 from .helpers import get_running_loop
+from .log import internal_logger
 
 __all__ = ("ThreadedResolver", "AsyncResolver", "DefaultResolver")
 
@@ -32,15 +33,21 @@ async def resolve(
         )
 
         hosts = []
-        for family, _, proto, _, address in infos:
-            if family == socket.AF_INET6 and address[3]:  # type: ignore
-                # This is essential for link-local IPv6 addresses.
-                # LL IPv6 is a VERY rare case. Strictly speaking, we should use
-                # getnameinfo() unconditionally, but performance makes sense.
-                host, _port = socket.getnameinfo(
-                    address, socket.NI_NUMERICHOST | socket.NI_NUMERICSERV
-                )
-                port = int(_port)
+        for info in infos:
+            family, _, proto, _, address = info
+            if family == socket.AF_INET6:
+                # https://github.com/aio-libs/aiohttp/issues/5156
+                if len(address) != 4:
+                    internal_logger.warning(f"Bad address format in {info}")
+                    continue
+                if address[3]:  # type: ignore
+                    # This is essential for link-local IPv6 addresses.
+                    # LL IPv6 is a VERY rare case. Strictly speaking, we should use
+                    # getnameinfo() unconditionally, but performance makes sense.
+                    host, _port = socket.getnameinfo(
+                        address, socket.NI_NUMERICHOST | socket.NI_NUMERICSERV
+                    )
+                    port = int(_port)
             else:
                 host, port = address[:2]
             hosts.append(