View at Official ubuntu advisory, NVD, CVE.org · CVE detail
Freshness: upstream tracker timestamp is available; use API updated time as primary recency signal.
CVE-2016-4456 medium priority: Ubuntu including 1 source packages (gnutls28), 5 status rows across 5 suites (precise, trusty, upstream, wily, xenial): not-affected 3, DNE 1, released 1.
The "GNUTLS_KEYLOGFILE" environment variable in gnutls 3.4.12 allows remote attackers to overwrite and corrupt arbitrary files in the filesystem.