diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index d647606..e699815 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -132,7 +132,8 @@
             is_w = obj.writable()
             if is_r:
                 r.append(fd)
-            if is_w:
+            # accepting sockets should not be writable
+            if is_w and not obj.accepting:
                 w.append(fd)
             if is_r or is_w:
                 e.append(fd)
@@ -179,7 +180,8 @@
             flags = 0
             if obj.readable():
                 flags |= select.POLLIN | select.POLLPRI
-            if obj.writable():
+            # accepting sockets should not be writable
+            if obj.writable() and not obj.accepting:
                 flags |= select.POLLOUT
             if flags:
                 # Only check for exceptions if object was either readable
diff --git a/Misc/NEWS b/Misc/NEWS
index a206a17..18c79a0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -225,6 +225,8 @@
 Library
 -------
 
+- Issue #12502: asyncore: fix polling loop with AF_UNIX sockets.
+
 - Issue #4376: ctypes now supports nested structures in a endian different than
   the parent structure. Patch by Vlad Riscutia.