diff --git a/build.gradle b/build.gradle
index 117b7c09..ce3c8f53 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,7 +21,7 @@ dependencies {
 	
 	// https://mvnrepository.com/artifact/org.apache.pdfbox/jbig2-imageio
 	implementation group: 'org.apache.pdfbox', name: 'jbig2-imageio', version: '3.0.4'
-	
+	implementation 'commons-io:commons-io:2.11.0'
 		
 	//general PDF
     implementation 'org.apache.pdfbox:pdfbox:2.0.27'
diff --git a/src/main/java/stirling/software/SPDF/controller/OCRController.java b/src/main/java/stirling/software/SPDF/controller/OCRController.java
index 0e2bd04b..3713cbda 100644
--- a/src/main/java/stirling/software/SPDF/controller/OCRController.java
+++ b/src/main/java/stirling/software/SPDF/controller/OCRController.java
@@ -6,6 +6,7 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -29,6 +30,7 @@ import org.springframework.web.servlet.ModelAndView;
 import stirling.software.SPDF.utils.ProcessExecutor;
 //import com.spire.pdf.*;
 import java.util.concurrent.Semaphore;
+import java.util.regex.Pattern;
 @Controller
 public class OCRController {
 
@@ -41,8 +43,6 @@ public class OCRController {
 		modelAndView.addObject("currentPage", "ocr-pdf");
 		return modelAndView;
 	}
-
-	private final Semaphore semaphore = new Semaphore(2);
 	
 	@PostMapping("/ocr-pdf")
 	public ResponseEntity<byte[]> processPdfWithOCR(@RequestParam("fileInput") MultipartFile inputFile,
@@ -59,9 +59,19 @@ public class OCRController {
 			throw new IOException("Please select at least one language.");
 	    }
 		
+		// Validate and sanitize selected languages using regex
+        String languagePattern = "^[a-zA-Z]{3}$"; // Regex pattern for three-letter language codes
+        selectedLanguages = selectedLanguages.stream()
+                .filter(lang -> Pattern.matches(languagePattern, lang))
+                .collect(Collectors.toList());
+
+        
+        if (selectedLanguages.isEmpty()) {
+            throw new IOException("None of the selected languages are valid.");
+        }
 		// Save the uploaded file to a temporary location
 		Path tempInputFile = Files.createTempFile("input_", ".pdf");
-		inputFile.transferTo(tempInputFile.toFile());
+		Files.copy(inputFile.getInputStream(), tempInputFile, StandardCopyOption.REPLACE_EXISTING);
 
 		// Prepare the output file path
 		Path tempOutputFile = Files.createTempFile("output_", ".pdf");
diff --git a/src/main/java/stirling/software/SPDF/controller/converters/ConvertOfficeController.java b/src/main/java/stirling/software/SPDF/controller/converters/ConvertOfficeController.java
index 71c8b461..ab2106aa 100644
--- a/src/main/java/stirling/software/SPDF/controller/converters/ConvertOfficeController.java
+++ b/src/main/java/stirling/software/SPDF/controller/converters/ConvertOfficeController.java
@@ -1,6 +1,7 @@
 package stirling.software.SPDF.controller.converters;
 
 import java.io.IOException;
+import java.nio.file.StandardCopyOption;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -14,7 +15,7 @@ import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.multipart.MultipartFile;
-
+import org.apache.commons.io.FilenameUtils;
 import stirling.software.SPDF.utils.PdfUtils;
 import stirling.software.SPDF.utils.ProcessExecutor;
 @Controller
@@ -39,14 +40,20 @@ public class ConvertOfficeController {
 	
 	
 public byte[] convertToPdf(MultipartFile inputFile) throws IOException, InterruptedException {
+ // Check for valid file extension
+    String originalFilename = inputFile.getOriginalFilename();
+    if (originalFilename == null || !isValidFileExtension(FilenameUtils.getExtension(originalFilename))) {
+        throw new IllegalArgumentException("Invalid file extension");
+    }
+
     // Save the uploaded file to a temporary location
-    Path tempInputFile = Files.createTempFile("input_", "." + getFileExtension(inputFile.getOriginalFilename()));
-    inputFile.transferTo(tempInputFile.toFile());
+    Path tempInputFile = Files.createTempFile("input_", "." + FilenameUtils.getExtension(originalFilename));
+    Files.copy(inputFile.getInputStream(), tempInputFile, StandardCopyOption.REPLACE_EXISTING);
 
     // Prepare the output file path
     Path tempOutputFile = Files.createTempFile("output_", ".pdf");
 
- // Run the LibreOffice command
+    // Run the LibreOffice command
     List<String> command = new ArrayList<>(Arrays.asList("unoconv", "-vvv",
             "-f",
             "pdf",
@@ -64,14 +71,8 @@ public byte[] convertToPdf(MultipartFile inputFile) throws IOException, Interrup
 
     return pdfBytes;
 }
-
-
-
-private String getFileExtension(String fileName) {
-    int dotIndex = fileName.lastIndexOf('.');
-    if (dotIndex == -1) {
-        return "";
-    }
-    return fileName.substring(dotIndex + 1);
+private boolean isValidFileExtension(String fileExtension) {
+    String extensionPattern = "^(?i)[a-z0-9]{2,4}$";
+    return fileExtension.matches(extensionPattern);
 }
 }