Double free vulnerability in the gnutls_x509_ext_import_proxy function in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allows remote attackers to have unspecified impact via crafted policy language information in an X.509 certificate with a Proxy Certificate Information extension. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-5334
