The Thomson ST 2030 SIP phone with software 1.52.1 allows remote attackers to cause a denial of service (device hang) via an INVITE message with a Via header that contains a '/' (slash) instead of the required space following the SIP version number.
https://exchange.xforce.ibmcloud.com/vulnerabilities/36217
http://www.vupen.com/english/advisories/2007/2988
http://www.securitytracker.com/id?1018603
http://www.securityfocus.com/bid/25446
http://securityreason.com/securityalert/3075
http://secunia.com/advisories/26587
http://lists.grok.org.uk/pipermail/full-disclosure/2007-August/065433.html