GHSA-f73w-xph4-pjp3: FreeSWITCH: Pre-authentication heap buffer overflow in core XML empty-entity decoding

FreeSWITCH is an open-source software telecommunications platform. Before version 1.11.2, an integer underflow in  switchxmldecode()  can cause an undersized heap allocation when an XML document declares an entity with an empty replacement value. Subsequent copying overruns the allocated buffer. An unauthenticated attacker who can reach a SIP profile with presence management enabled and DTD processing permitted can trigger the vulnerability through a crafted SIP PUBLISH request. Exploitation can corrupt heap memory and terminate the FreeSWITCH process, interrupting all active calls. This vulnerability is fixed in version 1.11.2.