diff --git a/ChangeLog b/ChangeLog
index 6764c4c..1e2f9b8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,12 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
-= mbed TLS 2.7.x released xxxx-xx-xx
+= mbed TLS x.x.x branch released xxxx-xx-xx
 
 Bugfix
+   * Change the shebang line in Perl scripts to look up perl in the PATH.
+     Contributed by fbrosson in #1533.
+   * Fix a memory leak in mbedtls_x509_csr_parse(), found by catenacyber,
+     Philippe Antoine.
    * Clarify documentation for mbedtls_ssl_write() to include 0 as a valid
      return value. Found by @davidwu2000. #839
 
diff --git a/library/x509_csr.c b/library/x509_csr.c
index 26a06db..779098d 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -278,34 +278,25 @@
         return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_PEM_PARSE_C)
-    mbedtls_pem_init( &pem );
-
     /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
-    if( buf[buflen - 1] != '\0' )
-        ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
-    else
+    if( buf[buflen - 1] == '\0' )
+    {
+        mbedtls_pem_init( &pem );
         ret = mbedtls_pem_read_buffer( &pem,
                                "-----BEGIN CERTIFICATE REQUEST-----",
                                "-----END CERTIFICATE REQUEST-----",
                                buf, NULL, 0, &use_len );
 
-    if( ret == 0 )
-    {
-        /*
-         * Was PEM encoded, parse the result
-         */
-        if( ( ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen ) ) != 0 )
-            return( ret );
+        if( ret == 0 )
+            /*
+             * Was PEM encoded, parse the result
+             */
+            ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen );
 
         mbedtls_pem_free( &pem );
-        return( 0 );
+        if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
+            return( ret );
     }
-    else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
-    {
-        mbedtls_pem_free( &pem );
-        return( ret );
-    }
-    else
 #endif /* MBEDTLS_PEM_PARSE_C */
     return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) );
 }
diff --git a/scripts/config.pl b/scripts/config.pl
index 5bf2785..468aeb9 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #
diff --git a/scripts/generate_errors.pl b/scripts/generate_errors.pl
index ac0fbff..4f0ad31 100755
--- a/scripts/generate_errors.pl
+++ b/scripts/generate_errors.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Generate error.c
 #
diff --git a/scripts/generate_features.pl b/scripts/generate_features.pl
index 2aa695c..1bd82ca 100755
--- a/scripts/generate_features.pl
+++ b/scripts/generate_features.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 
 use strict;
diff --git a/scripts/generate_visualc_files.pl b/scripts/generate_visualc_files.pl
index e042a44..811c71f 100755
--- a/scripts/generate_visualc_files.pl
+++ b/scripts/generate_visualc_files.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Generate main file, individual apps and solution files for MS Visual Studio
 # 2010
diff --git a/scripts/massif_max.pl b/scripts/massif_max.pl
index d1ce4ca..4e3342a 100755
--- a/scripts/massif_max.pl
+++ b/scripts/massif_max.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Parse a massif.out.xxx file and output peak total memory usage
 
diff --git a/scripts/rename.pl b/scripts/rename.pl
index c29519e..fb42809 100755
--- a/scripts/rename.pl
+++ b/scripts/rename.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #
diff --git a/tests/scripts/check-doxy-blocks.pl b/tests/scripts/check-doxy-blocks.pl
index b0fd696..4967699 100755
--- a/tests/scripts/check-doxy-blocks.pl
+++ b/tests/scripts/check-doxy-blocks.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Detect comment blocks that are likely meant to be doxygen blocks but aren't.
 #
diff --git a/tests/scripts/curves.pl b/tests/scripts/curves.pl
index 0041814..ddc90c5 100755
--- a/tests/scripts/curves.pl
+++ b/tests/scripts/curves.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # curves.pl
 #
diff --git a/tests/scripts/depends-hashes.pl b/tests/scripts/depends-hashes.pl
index 29dcfb0..f57e7ed 100755
--- a/tests/scripts/depends-hashes.pl
+++ b/tests/scripts/depends-hashes.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # depends-hashes.pl
 #
diff --git a/tests/scripts/depends-pkalgs.pl b/tests/scripts/depends-pkalgs.pl
index 14c92b2..97a43e8 100755
--- a/tests/scripts/depends-pkalgs.pl
+++ b/tests/scripts/depends-pkalgs.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # depends-pkalgs.pl
 #
diff --git a/tests/scripts/gen_ctr_drbg.pl b/tests/scripts/gen_ctr_drbg.pl
index ee13024..3c074be 100755
--- a/tests/scripts/gen_ctr_drbg.pl
+++ b/tests/scripts/gen_ctr_drbg.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST CTR_DRBG.rsp validation file
 # Only uses AES-256-CTR cases that use a Derivation function
diff --git a/tests/scripts/gen_gcm_decrypt.pl b/tests/scripts/gen_gcm_decrypt.pl
index 6decac2..03809cb 100755
--- a/tests/scripts/gen_gcm_decrypt.pl
+++ b/tests/scripts/gen_gcm_decrypt.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST gcmDecryptxxx.rsp validation files
 # Only first 3 of every set used for compile time saving
diff --git a/tests/scripts/gen_gcm_encrypt.pl b/tests/scripts/gen_gcm_encrypt.pl
index 8adbbce..29ec677 100755
--- a/tests/scripts/gen_gcm_encrypt.pl
+++ b/tests/scripts/gen_gcm_encrypt.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST gcmEncryptIntIVxxx.rsp validation files
 # Only first 3 of every set used for compile time saving
diff --git a/tests/scripts/gen_pkcs1_v21_sign_verify.pl b/tests/scripts/gen_pkcs1_v21_sign_verify.pl
index 678e2f9..110cb4b 100755
--- a/tests/scripts/gen_pkcs1_v21_sign_verify.pl
+++ b/tests/scripts/gen_pkcs1_v21_sign_verify.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 
 use strict;
diff --git a/tests/scripts/key-exchanges.pl b/tests/scripts/key-exchanges.pl
index d167c67..3bf7ae3 100755
--- a/tests/scripts/key-exchanges.pl
+++ b/tests/scripts/key-exchanges.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # key-exchanges.pl
 #
diff --git a/tests/scripts/list-enum-consts.pl b/tests/scripts/list-enum-consts.pl
index 633e3fd..21c25b3 100755
--- a/tests/scripts/list-enum-consts.pl
+++ b/tests/scripts/list-enum-consts.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use warnings;
 use strict;
diff --git a/tests/scripts/recursion.pl b/tests/scripts/recursion.pl
index 3ad42b1..431e592 100755
--- a/tests/scripts/recursion.pl
+++ b/tests/scripts/recursion.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Find functions making recursive calls to themselves.
 # (Multiple recursion where a() calls b() which calls a() not covered.)
diff --git a/tests/scripts/run-test-suites.pl b/tests/scripts/run-test-suites.pl
index 7e2974b..6279358 100755
--- a/tests/scripts/run-test-suites.pl
+++ b/tests/scripts/run-test-suites.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # run-test-suites.pl
 #
diff --git a/tests/scripts/test-ref-configs.pl b/tests/scripts/test-ref-configs.pl
index 600fc75..e1d2184 100755
--- a/tests/scripts/test-ref-configs.pl
+++ b/tests/scripts/test-ref-configs.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # test-ref-configs.pl
 #