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 version 1.11.0, FreeSWITCH includes a vulnerable function, PREFIX(prologTok)(), in libs/xmlrpc-c/lib/expat/xmltok/xmltok_impl.c, which was cloned from an outdated and vulnerable version in libexpat/libexpat. The function did not receive the corresponding security patch. This issue has been patched in version 1.11.0.