CVE-2026-45771: Freeswitch Denial-of-Service in SIP PUBLISH Requests via XML Entity Expansion

Vulnerability summary

CVE-2026-45771 is a high (CVSS 7.5) vulnerability in freeswitch. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 28.1% of scored vulnerabilities.

Timeline

1. 09-06-2026
   PublishedVulnerability first disclosed.
2. 09-06-2026
   Last modifiedVulnerability information updated.

Description

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's bundled XML parser expands nested <!ENTITY> declarations without a depth or count bound, so a small DTD can describe a body that expands exponentially ("billion laughs"). The PIDF body of a SIP PUBLISH is fed to this parser before any digest check, letting an unauthenticated network attacker force unbounded CPU and memory consumption with a single request. This issue has been patched in version 1.11.0.

• CWE-776Improper Restriction of Recursive Entity References in DTDsThe product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.