FreeSWITCH: Pre-authentication out-of-bounds write in MSRP message body parsing

Overview

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to 1.11.2, msrp_parse_buffer() subtracted delimiter framing from a peer-controlled short segment whose MSRP byte range ended in * without first proving the segment was long enough. The unsigned result wrapped near SIZE_MAX and reached switch_msrp_msg_set_payload() as both an allocation size and memcpy length, while related pointer arithmetic could read before the receive buffer. The listener is disabled by default in msrp.conf.xml, but any deployment enabling an MSRP TCP or TLS port parses this framing before authentication. An unauthenticated network peer can corrupt memory and crash FreeSWITCH, dropping all active calls, although remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.

Affected

• freeswitch < 1.11.2

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.