diff --git a/ChangeLog b/ChangeLog
index 6b69733..beb4dca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,11 @@
       some data loss when casting a size_t to an unsigned int value in the
       functions rsa_verify_wrap(), rsa_sign_wrap(), rsa_alt_sign_wrap() and
       pk_sign(). Found by Jean-Philippe Aumasson.
+   * Fixed potential livelock during the parsing of a CRL in PEM format in
+     mbedtls_x509_crl_parse(). A string containing a CRL followed by trailing
+     characters after the footer could result in the execution of an infinite
+     loop. The issue can be triggered remotely. Found by Greg Zaverucha,
+     Microsoft.
 
 Bugfix
    * Fixed multiple buffer overreads in mbedtls_pem_read_buffer() when parsing
diff --git a/library/x509_crl.c b/library/x509_crl.c
index de2079f..0d92bb1 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -525,7 +525,7 @@
 
             pem_free( &pem );
         }
-        else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
+        else if( is_pem )
         {
             pem_free( &pem );
             return( ret );
diff --git a/tests/data_files/crl-malformed-trailing-spaces.pem b/tests/data_files/crl-malformed-trailing-spaces.pem
new file mode 100644
index 0000000..9eae3da
--- /dev/null
+++ b/tests/data_files/crl-malformed-trailing-spaces.pem
@@ -0,0 +1,20 @@
+-----BEGIN X509 CRL-----
+MIIBbzCB9gIBATAJBgcqhkjOPQQBMD4xCzAJBgNVBAYTAk5MMREwDwYDVQQKEwhQ
+b2xhclNTTDEcMBoGA1UEAxMTUG9sYXJzc2wgVGVzdCBFQyBDQRcNMTMwOTI0MTYz
+MTA4WhcNMjMwOTIyMTYzMTA4WjAUMBICAQoXDTEzMDkyNDE2MjgzOFqgcjBwMG4G
+A1UdIwRnMGWAFJ1tICRJAT8ry3i1Gbx+JMnb+zZ8oUKkQDA+MQswCQYDVQQGEwJO
+TDERMA8GA1UEChMIUG9sYXJTU0wxHDAaBgNVBAMTE1BvbGFyc3NsIFRlc3QgRUMg
+Q0GCCQDBQ+J+YkPM6DAJBgcqhkjOPQQBA2kAMGYCMQDVG95rrSSl4dJgbJ5vR1GW
+svEuEsAh35EhF1WrcadMuCeMQVX9cUPupFfQUpHyMfoCMQCKf0yv8pN9BAoi3FVm
+56meWPhUekgLKKMAobt2oJJY6feuiFU2YFGs1aF0rV6Bj+U=
+-----END X509 CRL-----
+-----BEGIN X509 CRL-----
+MIIBcTCB9wIBATAKBggqhkjOPQQDBDA+MQswCQYDVQQGEwJOTDERMA8GA1UEChMI
+UG9sYXJTU0wxHDAaBgNVBAMTE1BvbGFyc3NsIFRlc3QgRUMgQ0EXDTEzMDkyNDE2
+MzEwOFoXDTIzMDkyMjE2MzEwOFowFDASAgEKFw0xMzA5MjQxNjI4MzhaoHIwcDBu
+BgNVHSMEZzBlgBSdbSAkSQE/K8t4tRm8fiTJ2/s2fKFCpEAwPjELMAkGA1UEBhMC
+TkwxETAPBgNVBAoTCFBvbGFyU1NMMRwwGgYDVQQDExNQb2xhcnNzbCBUZXN0IEVD
+IENBggkAwUPifmJDzOgwCgYIKoZIzj0EAwQDaQAwZgIxAL/VFrDIYUECsS0rVpAy
+6zt/CqeAZ1sa/l5LTaG1XW286n2Kibipr6EpkYZNYIQILgIxAI0wb3Py1DHPWpYf
+/BFBH7C3KYq+nWTrLeEnhrjU1LzG/CiQ8lnuskya6lw/P3lJ/A==
+-----END X509 CRL-----      
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index b289fc9..3dc7e03 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -194,6 +194,10 @@
 depends_on:POLARSSL_PEM_PARSE_C
 x509_crl_info:"data_files/crl-ec-sha512.pem":"CRL version   \: 2\nissuer name   \: C=NL, O=PolarSSL, CN=Polarssl Test EC CA\nthis update   \: 2013-09-24 16\:31\:08\nnext update   \: 2023-09-22 16\:31\:08\nRevoked certificates\:\nserial number\: 0A revocation date\: 2013-09-24 16\:28\:38\nsigned using  \: ECDSA with SHA512\n"
 
+X509 CRL Malformed Input (trailing spaces at end of file)
+depends_on:POLARSSL_PEM_PARSE_C
+x509_crl_parse:"data_files/crl-malformed-trailing-spaces.pem":POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT
+
 X509 CSR Information RSA with MD4
 depends_on:POLARSSL_PEM_PARSE_C
 x509_csr_info:"data_files/server1.req.md4":"CSR version   \: 1\nsubject name  \: C=NL, O=PolarSSL, CN=PolarSSL Server 1\nsigned using  \: RSA with MD4\nRSA key size  \: 2048 bits\n"
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index eee8241..4ae3c9f 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -167,6 +167,22 @@
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:POLARSSL_FS_IO:POLARSSL_X509_CRL_PARSE_C */
+void x509_crl_parse( char *crl_file, int result )
+{
+    x509_crl crl;
+    char buf[2000];
+
+    x509_crl_init( &crl );
+    memset( buf, 0, 2000 );
+
+    TEST_ASSERT( x509_crl_parse_file( &crl, crl_file ) == result );
+
+exit:
+    x509_crl_free( &crl );
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:POLARSSL_FS_IO:POLARSSL_X509_CSR_PARSE_C */
 void x509_csr_info( char *csr_file, char *result_str )
 {