Pidgin version <2.11.0 contains a vulnerability in X.509 Certificates imports specifically due to improper check of return values from gnutls_x509_crt_init() and gnutls_x509_crt_import() that can result in code execution. This attack appear to be exploitable via custom X.509 certificate from another client. This vulnerability appears to have been fixed in 2.11.0.
https://www.suse.com/pt-br/security/cve/CVE-2016-1000030/
https://security.gentoo.org/glsa/201701-38
https://pidgin.im/news/security/?id=91