nspr - security update

Two vulnerabilities were reported in NSPR, a library to abstract over
operating system interfaces developed by the Mozilla project.

• CVE-2016-1951
  q1 reported that the NSPR implementation of sprintf-style string
  formatting function miscomputed memory allocation sizes,
  potentially leading to heap-based buffer overflows

The second issue concerns environment variable processing in NSPR.
The library did not ignore environment variables used to configuring
logging and tracing in processes which underwent a SUID/SGID/AT_SECURE
transition at process start. In certain system configurations, this
allowed local users to escalate their privileges.

In addition, this nspr update contains further stability and
correctness fixes and contains support code for an upcoming nss
update.

For the stable distribution (jessie), these problems have been fixed
in version 2:4.12-1+debu8u1.

For the unstable distribution (sid), these problems have been fixed in
version 2:4.12-1.

We recommend that you upgrade your nspr packages.