diff --git a/source/build/include/build.h b/source/build/include/build.h
index a1c1f6a75c2..02f975d0de7 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -354,7 +354,7 @@ void allocateMapArrays(int numsprites);
 void ValidateSprite(spritetype& spr);
 void engineLoadBoard(const char *filename, int flags, vec3_t *dapos, int16_t *daang, int *dacursectnum);
 void loadMapBackup(const char* filename);
-void G_LoadMapHack(const char* filename, const unsigned char*);
+void G_LoadMapHack(const char* filename, const unsigned char*, spritetype*, int);
 
 void   videoSetCorrectedAspect();
 void   videoSetViewableArea(int32_t x1, int32_t y1, int32_t x2, int32_t y2);
diff --git a/source/core/maphack.cpp b/source/core/maphack.cpp
index 91d7c07b768..f16617e2ad9 100644
--- a/source/core/maphack.cpp
+++ b/source/core/maphack.cpp
@@ -48,7 +48,7 @@ void AddUserMapHack(usermaphack_t& mhk)
     usermaphacks.Push(mhk);
 }
 
-static int32_t LoadMapHack(const char *filename)
+static int32_t LoadMapHack(const char *filename, spritetype* sprites, int numsprites)
 {
     int currentsprite = -1;
     int currentwall = -1;
@@ -67,7 +67,7 @@ static int32_t LoadMapHack(const char *filename)
         FString token = sc.String;
         auto validateSprite = [&]()
         {
-            if (currentsprite < 0)
+            if (currentsprite < 0 || currentsprite >= numsprites)
             {
                 sc.ScriptMessage("Using %s without a valid sprite", token.GetChars());
                 return false;
@@ -77,7 +77,7 @@ static int32_t LoadMapHack(const char *filename)
 
         auto validateWall = [&]()
         {
-            if (currentwall < 0)
+            if (currentwall < 0 || currentwall >= numwalls)
             {
                 sc.ScriptMessage("Using %s without a valid wall", token.GetChars());
                 return false;
@@ -87,7 +87,7 @@ static int32_t LoadMapHack(const char *filename)
 
         auto validateSector = [&]()
         {
-            if (currentsector < 0)
+            if (currentsector < 0 || currentsector >= numsectors)
             {
                 sc.ScriptMessage("Using %s without a valid sector", token.GetChars());
                 return false;
@@ -154,7 +154,7 @@ static int32_t LoadMapHack(const char *filename)
             {
                 if (currentsprite != -1 && validateSprite())
                 {
-                    sprite[currentsprite].sectnum = sc.Number;
+                    sprites[currentsprite].sectnum = sc.Number;
                 }
             }
         }
@@ -168,7 +168,7 @@ static int32_t LoadMapHack(const char *filename)
                 }
                 else if (currentsprite != -1 && validateSprite())
                 {
-                    sprite[currentsprite].picnum = sc.Number;
+                    sprites[currentsprite].picnum = sc.Number;
                 }
             }
         }
@@ -219,7 +219,7 @@ static int32_t LoadMapHack(const char *filename)
                 }
                 else if (currentsprite != -1 && validateSprite())
                 {
-                    sprite[currentsprite].cstat &= ~sc.Number;
+                    sprites[currentsprite].cstat &= ~sc.Number;
                 }
             }
         }
@@ -233,7 +233,7 @@ static int32_t LoadMapHack(const char *filename)
                 }
                 else if (currentsprite != -1 && validateSprite())
                 {
-                    sprite[currentsprite].cstat |= sc.Number;
+                    sprites[currentsprite].cstat |= sc.Number;
                 }
             }
         }
@@ -247,7 +247,7 @@ static int32_t LoadMapHack(const char *filename)
                 }
                 else if (currentsprite != -1 && validateSprite())
                 {
-                    sprite[currentsprite].lotag = sc.Number;
+                    sprites[currentsprite].lotag = sc.Number;
                 }
             }
         }
@@ -374,7 +374,7 @@ static int32_t LoadMapHack(const char *filename)
 	return 0;
 }
 
-void G_LoadMapHack(const char* filename, const unsigned char* md4)
+void G_LoadMapHack(const char* filename, const unsigned char* md4, spritetype* sprites, int numsprites)
 {
     hw_ClearSplitSector();
     blockingpairs.Reset();
@@ -384,16 +384,16 @@ void G_LoadMapHack(const char* filename, const unsigned char* md4)
     {
         internal.AppendFormat("%02x", md4[j]);
     }
-    LoadMapHack(internal + ".mhk");
+    LoadMapHack(internal + ".mhk", sprites, numsprites);
     FString hack = StripExtension(filename) + ".mhk";
 
-    if (LoadMapHack(hack))
+    if (LoadMapHack(hack, sprites, numsprites))
     {
         for (auto& mhk : usermaphacks)
         {
             if (!memcmp(md4, mhk.md4, 16))
             {
-                LoadMapHack(mhk.mhkfile);
+                LoadMapHack(mhk.mhkfile, sprites, numsprites);
             }
         }
     }
diff --git a/source/core/maploader.cpp b/source/core/maploader.cpp
index 312d752b6ea..ab32c7e4e39 100644
--- a/source/core/maploader.cpp
+++ b/source/core/maploader.cpp
@@ -513,7 +513,7 @@ void engineLoadBoard(const char* filename, int flags, vec3_t* pos, int16_t* ang,
 	auto buffer = fr.Read();
 	unsigned char md4[16];
 	md4once(buffer.Data(), buffer.Size(), md4);
-	G_LoadMapHack(filename, md4);
+	G_LoadMapHack(filename, md4, sprite, numsprites);
 	setWallSectors();
 	hw_BuildSections();
 	sectorGeometry.SetSize(numsections);
diff --git a/source/games/blood/src/db.cpp b/source/games/blood/src/db.cpp
index bd2f3a0df5c..741023cd35d 100644
--- a/source/games/blood/src/db.cpp
+++ b/source/games/blood/src/db.cpp
@@ -885,7 +885,7 @@ void dbLoadMap(const char* pPath, int* pX, int* pY, int* pZ, short* pAngle, sect
     auto buffer = fr.Read();
     uint8_t md4[16];
     md4once(buffer.Data(), buffer.Size(), md4);
-    G_LoadMapHack(mapname, md4);
+    G_LoadMapHack(mapname, md4, sprite, mapHeader.numsprites);
 
     if (CalcCRC32(buffer.Data(), buffer.Size() - 4) != nCRC)
     {