diff --git a/libnm-core/nm-keyfile-utils.c b/libnm-core/nm-keyfile-utils.c
index 1b7860d873..8858331949 100644
--- a/libnm-core/nm-keyfile-utils.c
+++ b/libnm-core/nm-keyfile-utils.c
@@ -442,7 +442,7 @@ _keyfile_key_encode (const char *name,
 		        && g_ascii_isxdigit (name[i + 2]))
 		    || (   ch == ' '
 		        && name[i + 1] == '\0'))
-			g_string_append_printf (str, "\\%2X", ch);
+			g_string_append_printf (str, "\\%02X", ch);
 		else
 			g_string_append_c (str, (char) ch);
 	}
diff --git a/libnm-core/tests/test-keyfile.c b/libnm-core/tests/test-keyfile.c
index 2dc929afd8..313932f0f0 100644
--- a/libnm-core/tests/test-keyfile.c
+++ b/libnm-core/tests/test-keyfile.c
@@ -99,6 +99,11 @@ test_encode_key (void)
 	do_test_encode_key_bijection (kf, "   ", "\\20 \\20");
 	do_test_encode_key_decode_surjection (kf, "f\\20c", "f c");
 	do_test_encode_key_decode_surjection (kf, "\\20\\20\\20", "\\20 \\20");
+
+	do_test_encode_key_bijection (kf, "\t", "\\09");
+	do_test_encode_key_bijection (kf, "\t=x", "\\09\\3Dx");
+	do_test_encode_key_bijection (kf, "(nm-openvpn-auth-dialog:10283): GdkPixbuf-DEBUG: \tCopy pixels == false",
+	                                  "(nm-openvpn-auth-dialog:10283): GdkPixbuf-DEBUG: \\09Copy pixels \\3D\\3D false");
 }
 
 /*****************************************************************************/