src/net/ipsock_posix.go |  6 +++++-
 src/net/udpsock_test.go | 32 ++++++++++++++++++++++++++++++++

diff --git a/src/net/ipsock_posix.go b/src/net/ipsock_posix.go
index 2aeabd44873f223f49aadb73ead56b6ef9b4dc6b..52712f932f7530e8f62cb41cccffc994d4e9b7be 100644
--- a/src/net/ipsock_posix.go
+++ b/src/net/ipsock_posix.go
@@ -237,8 +237,12 @@
 func addrPortToSockaddrInet4(ap netip.AddrPort) (syscall.SockaddrInet4, error) {
 	// ipToSockaddrInet4 has special handling here for zero length slices.
 	// We do not, because netip has no concept of a generic zero IP address.
+	//
+	// addr is allowed to be an IPv4-mapped IPv6 address.
+	// As4 will unmap it to an IPv4 address.
+	// The error message is kept consistent with ipToSockaddrInet4.
 	addr := ap.Addr()
-	if !addr.Is4() {
+	if !addr.Is4() && !addr.Is4In6() {
 		return syscall.SockaddrInet4{}, &AddrError{Err: "non-IPv4 address", Addr: addr.String()}
 	}
 	sa := syscall.SockaddrInet4{
diff --git a/src/net/udpsock_test.go b/src/net/udpsock_test.go
index 6dacc81df6e059f85e564d642ab6f830c90759bc..7ad8a585b07e335ecbc1686ebf967a724c8d39fe 100644
--- a/src/net/udpsock_test.go
+++ b/src/net/udpsock_test.go
@@ -705,3 +705,35 @@ 	if err != nil {
 		t.Fatal(err)
 	}
 }
+
+// TestIPv4WriteMsgUDPAddrPortTargetAddrIPVersion verifies that
+// WriteMsgUDPAddrPort accepts IPv4 and IPv4-mapped IPv6 destination addresses,
+// and rejects IPv6 destination addresses on a "udp4" connection.
+func TestIPv4WriteMsgUDPAddrPortTargetAddrIPVersion(t *testing.T) {
+	if !testableNetwork("udp4") {
+		t.Skipf("skipping: udp4 not available")
+	}
+
+	conn, err := ListenUDP("udp4", &UDPAddr{IP: IPv4(127, 0, 0, 1)})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	daddr4 := netip.AddrPortFrom(netip.MustParseAddr("127.0.0.1"), 12345)
+	daddr4in6 := netip.AddrPortFrom(netip.MustParseAddr("::ffff:127.0.0.1"), 12345)
+	daddr6 := netip.AddrPortFrom(netip.MustParseAddr("::1"), 12345)
+	buf := make([]byte, 8)
+
+	if _, _, err = conn.WriteMsgUDPAddrPort(buf, nil, daddr4); err != nil {
+		t.Errorf("conn.WriteMsgUDPAddrPort(buf, nil, daddr4) failed: %v", err)
+	}
+
+	if _, _, err = conn.WriteMsgUDPAddrPort(buf, nil, daddr4in6); err != nil {
+		t.Errorf("conn.WriteMsgUDPAddrPort(buf, nil, daddr4in6) failed: %v", err)
+	}
+
+	if _, _, err = conn.WriteMsgUDPAddrPort(buf, nil, daddr6); err == nil {
+		t.Errorf("conn.WriteMsgUDPAddrPort(buf, nil, daddr6) should have failed, but got no error")
+	}
+}