diff --git a/debian/libwireshark0.symbols b/debian/libwireshark0.symbols
index c76ae8eb6a..a984be7929 100644
--- a/debian/libwireshark0.symbols
+++ b/debian/libwireshark0.symbols
@@ -1116,6 +1116,7 @@ libwireshark.so.0 libwireshark0 #MINVER#
  proto_find_first_finfo@Base 2.3.0
  proto_find_undecoded_data@Base 1.99.3
  proto_free_deregistered_fields@Base 1.12.2
+ proto_free_field_strings@Base 3.1.1
  proto_get_data_protocol@Base 1.9.1
  proto_get_finfo_ptr_array@Base 1.9.1
  proto_get_first_protocol@Base 1.9.1
diff --git a/epan/proto.c b/epan/proto.c
index 70ccbfa641..968ced5aae 100644
--- a/epan/proto.c
+++ b/epan/proto.c
@@ -7675,6 +7675,95 @@ proto_add_deregistered_data (void *data)
 	g_ptr_array_add(deregistered_data, data);
 }
 
+void proto_free_field_strings (ftenum_t field_type, unsigned int field_display, const void *field_strings)
+{
+	if (field_strings == NULL) {
+		return;
+	}
+
+	switch (field_type) {
+		case FT_FRAMENUM:
+			/* This is just an integer represented as a pointer */
+			break;
+		case FT_PROTOCOL: {
+			protocol_t *protocol = (protocol_t *)field_strings;
+			g_free((gchar *)protocol->short_name);
+			break;
+		}
+		case FT_BOOLEAN: {
+			true_false_string *tf = (true_false_string *)field_strings;
+			g_free((gchar *)tf->true_string);
+			g_free((gchar *)tf->false_string);
+			break;
+		}
+		case FT_UINT40:
+		case FT_INT40:
+		case FT_UINT48:
+		case FT_INT48:
+		case FT_UINT56:
+		case FT_INT56:
+		case FT_UINT64:
+		case FT_INT64: {
+			/*
+			 * XXX - if it's BASE_RANGE_STRING, or
+			 * BASE_EXT_STRING, should we free it?
+			 */
+			if (field_display & BASE_UNIT_STRING) {
+				unit_name_string *unit = (unit_name_string *)field_strings;
+				g_free((gchar *)unit->singular);
+				g_free((gchar *)unit->plural);
+			} else {
+				val64_string *vs64 = (val64_string *)field_strings;
+				while (vs64->strptr) {
+					g_free((gchar *)vs64->strptr);
+					vs64++;
+				}
+			}
+			break;
+		}
+		case FT_CHAR:
+		case FT_UINT8:
+		case FT_INT8:
+		case FT_UINT16:
+		case FT_INT16:
+		case FT_UINT24:
+		case FT_INT24:
+		case FT_UINT32:
+		case FT_INT32:
+		case FT_FLOAT:
+		case FT_DOUBLE: {
+			/*
+			 * XXX - if it's BASE_RANGE_STRING, or
+			 * BASE_EXT_STRING, should we free it?
+			 */
+			if (field_display & BASE_UNIT_STRING) {
+				unit_name_string *unit = (unit_name_string *)field_strings;
+				g_free((gchar *)unit->singular);
+				g_free((gchar *)unit->plural);
+			} else if (field_display & BASE_RANGE_STRING) {
+				range_string *rs = (range_string *)field_strings;
+				while (rs->strptr) {
+					g_free((gchar *)rs->strptr);
+					rs++;
+				}
+			} else {
+				value_string *vs = (value_string *)field_strings;
+				while (vs->strptr) {
+					g_free((gchar *)vs->strptr);
+					vs++;
+				}
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (field_type != FT_FRAMENUM) {
+		g_free((void *)field_strings);
+	}
+}
+
 static void
 free_deregistered_field (gpointer data, gpointer user_data _U_)
 {
@@ -7685,88 +7774,7 @@ free_deregistered_field (gpointer data, gpointer user_data _U_)
 	g_free((char *)hfi->abbrev);
 	g_free((char *)hfi->blurb);
 
-	if (hfi->strings) {
-		switch (hfi->type) {
-			case FT_FRAMENUM:
-				/* This is just an integer represented as a pointer */
-				break;
-			case FT_PROTOCOL: {
-				protocol_t *protocol = (protocol_t *)hfi->strings;
-				g_free((gchar *)protocol->short_name);
-				break;
-			}
-			case FT_BOOLEAN: {
-				true_false_string *tf = (true_false_string *)hfi->strings;
-				g_free ((gchar *)tf->true_string);
-				g_free ((gchar *)tf->false_string);
-				break;
-			}
-			case FT_UINT40:
-			case FT_INT40:
-			case FT_UINT48:
-			case FT_INT48:
-			case FT_UINT56:
-			case FT_INT56:
-			case FT_UINT64:
-			case FT_INT64: {
-				/*
-				 * XXX - if it's BASE_RANGE_STRING, or
-				 * BASE_EXT_STRING, should we free it?
-				 */
-				if (hfi->display & BASE_UNIT_STRING) {
-					unit_name_string *unit = (unit_name_string*)hfi->strings;
-					g_free ((gchar *)unit->singular);
-					g_free ((gchar *)unit->plural);
-				} else {
-					val64_string *vs64 = (val64_string *)hfi->strings;
-					while (vs64->strptr) {
-						g_free((gchar *)vs64->strptr);
-						vs64++;
-					}
-				}
-				break;
-			}
-			case FT_CHAR:
-			case FT_UINT8:
-			case FT_INT8:
-			case FT_UINT16:
-			case FT_INT16:
-			case FT_UINT24:
-			case FT_INT24:
-			case FT_UINT32:
-			case FT_INT32:
-			case FT_FLOAT:
-			case FT_DOUBLE: {
-				/*
-				 * XXX - if it's BASE_RANGE_STRING, or
-				 * BASE_EXT_STRING, should we free it?
-				 */
-				if (hfi->display & BASE_UNIT_STRING) {
-					unit_name_string *unit = (unit_name_string*)hfi->strings;
-					g_free ((gchar *)unit->singular);
-					g_free ((gchar *)unit->plural);
-                                } else  if (hfi->display & BASE_RANGE_STRING) {
-					range_string *rs = (range_string *)hfi->strings;
-					while (rs->strptr) {
-						g_free((gchar *)rs->strptr);
-						rs++;
-					}
-				} else {
-					value_string *vs = (value_string *)hfi->strings;
-					while (vs->strptr) {
-						g_free((gchar *)vs->strptr);
-						vs++;
-					}
-				}
-				break;
-			default:
-				break;
-			}
-		}
-		if (hfi->type != FT_FRAMENUM) {
-			g_free((void *)hfi->strings);
-		}
-	}
+	proto_free_field_strings(hfi->type, hfi->display, hfi->strings);
 
 	if (hfi->parent == -1)
 		g_slice_free(header_field_info, hfi);
diff --git a/epan/proto.h b/epan/proto.h
index 9ba43f1be4..3abca93ed5 100644
--- a/epan/proto.h
+++ b/epan/proto.h
@@ -2380,6 +2380,13 @@ proto_deregister_field (const int parent, gint hf_id);
 WS_DLL_PUBLIC void
 proto_add_deregistered_data (void *data);
 
+/** Free strings in a field.
+ @param field_type the field type (one of FT_ values)
+ @param field_display field display value (one of BASE_ values)
+ @param field_strings field strings */
+WS_DLL_PUBLIC void
+proto_free_field_strings (ftenum_t field_type, unsigned int field_display, const void *field_strings);
+
 /** Free fields deregistered in proto_deregister_field(). */
 WS_DLL_PUBLIC void
 proto_free_deregistered_fields (void);
diff --git a/epan/wslua/wslua_proto.c b/epan/wslua/wslua_proto.c
index 6ecc3de341..48ff4c6bda 100644
--- a/epan/wslua/wslua_proto.c
+++ b/epan/wslua/wslua_proto.c
@@ -638,6 +638,7 @@ int wslua_deregister_protocols(lua_State* L) {
             /* Memory ownership was previously transferred to epan in Proto_commit */
             f->name = NULL;
             f->abbrev = NULL;
+            f->vs = NULL;
             f->blob = NULL;
 
             f->hfid = -2; /* Deregister ProtoField, freed in ProtoField__gc */
diff --git a/epan/wslua/wslua_proto_field.c b/epan/wslua/wslua_proto_field.c
index c050cdefbc..0a8394704f 100644
--- a/epan/wslua/wslua_proto_field.c
+++ b/epan/wslua/wslua_proto_field.c
@@ -1462,10 +1462,11 @@ static int ProtoField__gc(lua_State* L) {
         return 0;
     }
 
-    /* Note: name, abbrev and blob will be NULL after Proto deregistration. */
+    /* Note: name, abbrev, blob and vs will be NULL after Proto deregistration. */
     g_free(f->name);
     g_free(f->abbrev);
     g_free(f->blob);
+    proto_free_field_strings(f->type, f->base, f->vs);
     g_free(f);
 
     return 0;
diff --git a/test/lua/protofield.lua b/test/lua/protofield.lua
index 1cfc9fa184..2fcfafb2fd 100644
--- a/test/lua/protofield.lua
+++ b/test/lua/protofield.lua
@@ -79,7 +79,7 @@ test("ProtoField-char", success)
 success = pcall(ProtoField.new, "char base NONE without valuestring", "test.char1", ftypes.CHAR, nil, base.NONE)
 test("ProtoField-char-without-valuestring", not success)
 
-success, test_proto.fields.char2 = pcall(ProtoField.new, "char base NONE with valuestring", "test.char2", ftypes.CHAR, {1, "Value"}, base.NONE)
+success = pcall(ProtoField.new, "char base NONE with valuestring", "test.char2", ftypes.CHAR, {1, "Value"}, base.NONE)
 test("ProtoField-char-with-valuestring", success)
 
 success = pcall(ProtoField.new, "char base DEC", "test.char3", ftypes.CHAR, nil, base.DEC)
@@ -88,7 +88,7 @@ test("ProtoField-char-base-dec", not success)
 success = pcall(ProtoField.new, "char base UNIT_STRING", "test.char4", ftypes.CHAR, {" m"}, base.UNIT_STRING)
 test("ProtoField-char-unit-string", not success)
 
-success, test_proto.fields.char5 = pcall(ProtoField.new, "char base RANGE_STRING", "test.char5", ftypes.CHAR, {{1, 2, "Value"}}, base.RANGE_STRING)
+success = pcall(ProtoField.new, "char base RANGE_STRING", "test.char5", ftypes.CHAR, {{1, 2, "Value"}}, base.RANGE_STRING)
 test("ProtoField-char-range-string", success)
 
 -- Field name: empty, illegal, incompatible