The (1) bundled GnuTLS SSL/TLS plugin and the (2) bundled OpenSSL SSL/TLS plugin in libpurple in Pidgin before 2.10.10 do not properly consider the Basic Constraints extension during verification of X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

markup.c in the MXit protocol plugin in libpurple in Pidgin before 2.10.10 allows remote servers to cause a denial of service (application crash) via a large length value in an emoticon response.

nmevent.c in the Novell GroupWise protocol plugin in libpurple in Pidgin before 2.10.10 allows remote servers to cause a denial of service (application crash) via a crafted server message that triggers a large memory allocation.

Absolute path traversal vulnerability in the untar_block function in win32/untar.c in Pidgin before 2.10.10 on Windows allows remote attackers to write to arbitrary files via a drive name in a tar archive of a smiley theme.

The jabber_idn_validate function in jutil.c in the Jabber protocol plugin in libpurple in Pidgin before 2.10.10 allows remote attackers to obtain sensitive information from process memory via a crafted XMPP message.