diff --git a/src/net/udpsock.go b/src/net/udpsock.go
index 622b1f83fb..6d29a39edf 100644
--- a/src/net/udpsock.go
+++ b/src/net/udpsock.go
@@ -99,16 +99,12 @@ func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
 	return addrs.forResolve(network, address).(*UDPAddr), nil
 }
 
-// UDPAddrFromAddrPort returns addr as a UDPAddr.
-//
-// If addr is not valid, it returns nil.
+// UDPAddrFromAddrPort returns addr as a UDPAddr. If addr.IsValid() is false,
+// then the returned UDPAddr will contain a nil IP field, indicating an
+// address family-agnostic unspecified address.
 func UDPAddrFromAddrPort(addr netip.AddrPort) *UDPAddr {
-	if !addr.IsValid() {
-		return nil
-	}
-	ip16 := addr.Addr().As16()
 	return &UDPAddr{
-		IP:   IP(ip16[:]),
+		IP:   addr.Addr().AsSlice(),
 		Zone: addr.Addr().Zone(),
 		Port: int(addr.Port()),
 	}
@@ -189,7 +185,9 @@ func (c *UDPConn) ReadFromUDPAddrPort(b []byte) (n int, addr netip.AddrPort, err
 func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
 	var ap netip.AddrPort
 	n, oobn, flags, ap, err = c.ReadMsgUDPAddrPort(b, oob)
-	addr = UDPAddrFromAddrPort(ap)
+	if ap.IsValid() {
+		addr = UDPAddrFromAddrPort(ap)
+	}
 	return
 }
 
diff --git a/src/net/udpsock_test.go b/src/net/udpsock_test.go
index 9fe74f47a2..01b8d39216 100644
--- a/src/net/udpsock_test.go
+++ b/src/net/udpsock_test.go
@@ -603,3 +603,35 @@ func BenchmarkWriteToReadFromUDPAddrPort(b *testing.B) {
 		}
 	}
 }
+
+func TestUDPIPVersionReadMsg(t *testing.T) {
+	conn, err := ListenUDP("udp4", &UDPAddr{IP: IPv4(127, 0, 0, 1)})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+	daddr := conn.LocalAddr().(*UDPAddr).AddrPort()
+	buf := make([]byte, 8)
+	_, err = conn.WriteToUDPAddrPort(buf, daddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, _, _, saddr, err := conn.ReadMsgUDPAddrPort(buf, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !saddr.Addr().Is4() {
+		t.Error("returned AddrPort is not IPv4")
+	}
+	_, err = conn.WriteToUDPAddrPort(buf, daddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, _, _, soldaddr, err := conn.ReadMsgUDP(buf, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(soldaddr.IP) != 4 {
+		t.Error("returned UDPAddr is not IPv4")
+	}
+}