libidn - security update

Multiple vulnerabilities have been discovered in libidn. The Common
Vulnerabilities and Exposures project identifies the following problems:

• CVE-2015-8948
  When idn is reading one zero byte as input an out-of-bounds-read occurred.
• CVE-2016-6261
  An out-of-bounds stack read is exploitable in idna_to_ascii_4i.
• CVE-2016-6263
  stringprep_utf8_nfkc_normalize reject invalid UTF-8, causes a crash.

For Debian 7 Wheezy, these problems have been fixed in version
1.25-2+deb7u2.

We recommend that you upgrade your libidn packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: <https://wiki.debian.org/LTS&gt;