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-2015-5296 medium priority: Ubuntu including 2 source packages (samba, samba4), 16 status rows across 8 suites (precise, trusty, upstream, vivid, wily, xenial, yakkety, zesty): released 9, DNE 6, ignored 1.
Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 supports connections that are encrypted but unsigned, which allows man-in-the-middle attackers to conduct encrypted-to-unencrypted downgrade attacks by modifying the client-server data stream, related to clidfs.c, libsmb_server.c, and smbXcli_base.c.