diff --git a/src/resourcefiles/file_wad.cpp b/src/resourcefiles/file_wad.cpp
index c7a3a262f..a0ae033db 100644
--- a/src/resourcefiles/file_wad.cpp
+++ b/src/resourcefiles/file_wad.cpp
@@ -188,6 +188,17 @@ bool FWadFile::Open(bool quiet)
 		Lumps[i].Namespace = ns_global;
 		Lumps[i].Flags = Lumps[i].Compressed? LUMPF_COMPRESSED : 0;
 		Lumps[i].FullName = NULL;
+		
+		// Check if the lump is within the WAD file and print a warning if not.
+		if (Lumps[i].Position + Lumps[i].LumpSize > wadSize || Lumps[i].Position < 0 || Lumps[i].LumpSize < 0)
+		{
+			if (Lumps[i].LumpSize != 0)
+			{
+				Printf(PRINT_HIGH, "%s: Lump %s contains invalid positioning info and will be ignored\n", Filename, Lumps[i].Name);
+				Lumps[i].Name[0] = 0;
+			}
+			Lumps[i].LumpSize = Lumps[i].Position = 0;
+		}
 	}
 
 	delete[] fileinfo;