Samba is an open-source implementation of the Server Message Block or Common Internet File System protocol, which allows PC-compatible machines to share files, printers, and other information. A man-in-the-middle vulnerability was found in the way "connection signing" was implemented by Samba. A remote attacker could use this flaw to downgrade an existing Samba client connection and force the use of plain text. A missing access control flaw was found in Samba. A remote, authenticated attacker could use this flaw to view the current snapshot on a Samba share, despite not having DIRECTORY_LIST access rights. An access flaw was found in the way Samba verified symbolic links when creating new files on a Samba share. A remote attacker could exploit this flaw to gain access to files outside of Samba"s share path. Red Hat would like to thank the Samba project for reporting these issues. Upstream acknowledges Stefan Metzmacher of the Samba Team and Sernet.de as the original reporters of CVE-2015-5296, partha exablox com as the original reporter of CVE-2015-5299, Jan "Yenya" Kasprzak and the Computer Systems Unit team at Faculty of Informatics, Masaryk University as the original reporters of CVE-2015-5252. All samba users are advised to upgrade to these updated packages, which contain a backported patch to correct this issue. After installing this update, the smb service will be restarted automatically.