diff --git a/libmineziper/src/libmineziper.c b/libmineziper/src/libmineziper.c
index 0515ac9..481bce3 100644
--- a/libmineziper/src/libmineziper.c
+++ b/libmineziper/src/libmineziper.c
@@ -56,7 +56,7 @@ bool scan_decoded_files(zip zip)
     // Verify CDH/LFH parsed sizes to avoid undefined behavior
     if (lfh->filename_length != zip.cdh_filename_length[i])
     {
-      printf("[ERROR] Mismatch in CDH/LFH filename lengths.\n");
+      fprintf(stderr, "[ERROR] Mismatch in CDH/LFH filename lengths.\n");
       return true;
     }
 
diff --git a/libmineziper/src/libmineziper_zip.c b/libmineziper/src/libmineziper_zip.c
index b42007f..63c2022 100644
--- a/libmineziper/src/libmineziper_zip.c
+++ b/libmineziper/src/libmineziper_zip.c
@@ -33,7 +33,7 @@ void get_eocd(zip* z)
 
       if (!z->lfh_off || !z->cdh_filename_length)
       {
-        printf(
+        fprintf(stderr, 
             "[ERROR] Failed to allocate CDH/LFH buffer for %d entries\n",
             z->entries);
         exit(1);
@@ -86,7 +86,7 @@ char* decode_type1_block_vuln(bitstream* bs, char* decoded_data)
 
       if ((token = next_token(bs, tr_dist)) == END_OF_BLOCK)
       {
-        printf("[ERROR] Got EndOfBlock when decoding distance token\n");
+        fprintf(stderr, "[ERROR] Got EndOfBlock when decoding distance token\n");
         exit(1);
       }
 
@@ -126,7 +126,7 @@ char* decode_type1_block_v2(
 
       if ((token = next_token(bs, tr_dist)) == END_OF_BLOCK)
       {
-        printf("[ERROR] Got EndOfBlock when decoding distance token\n");
+        fprintf(stderr, "[ERROR] Got EndOfBlock when decoding distance token\n");
         exit(1);
       }
 
diff --git a/mineziper/mineziper.c b/mineziper/mineziper.c
index 4804674..20007ee 100644
--- a/mineziper/mineziper.c
+++ b/mineziper/mineziper.c
@@ -26,7 +26,7 @@ int main(int argc, char** argv)
 
   if (scan_zip(buf, read_size))
   {
-    printf("[ERROR] Cannot upload file, potential virus detected\n");
+    fprintf(stderr, "[ERROR] Cannot upload file, potential virus detected\n");
   }
   else
   {