diff --git a/third_party/libtiff/tif_dirread.c b/third_party/libtiff/tif_dirread.c
index bc4102184..0e3f8ccd4 100644
--- a/third_party/libtiff/tif_dirread.c
+++ b/third_party/libtiff/tif_dirread.c
@@ -4983,6 +4983,11 @@ TIFFFetchNormalTag(TIFF* tif, TIFFDirEntry* dp, int recover)
                                        if (err==TIFFReadDirEntryErrOk)
                                        {
                                                int m;
+                                               if( dp->tdir_count > 0 && data[dp->tdir_count-1] != '\0' )
+                        {
+                            TIFFWarningExt(tif->tif_clientdata,module,"ASCII value for tag \"%s\" does not end in null byte. Forcing it to be null",fip->field_name);
+                            data[dp->tdir_count-1] = '\0';
+                        }
                                                m=TIFFSetField(tif,dp->tdir_tag,(uint16)(dp->tdir_count),data);
                                                if (data!=0)
                                                        _TIFFfree(data);
@@ -5155,6 +5160,11 @@ TIFFFetchNormalTag(TIFF* tif, TIFFDirEntry* dp, int recover)
                                if (err==TIFFReadDirEntryErrOk)
                                {
                                        int m;
+                                       if( dp->tdir_count > 0 && data[dp->tdir_count-1] != '\0' )
+                    {
+                        TIFFWarningExt(tif->tif_clientdata,module,"ASCII value for tag \"%s\" does not end in null byte. Forcing it to be null",fip->field_name);
+                        data[dp->tdir_count-1] = '\0';
+                    }
                                        m=TIFFSetField(tif,dp->tdir_tag,(uint32)(dp->tdir_count),data);
                                        if (data!=0)
                                                _TIFFfree(data);