CVE-2026-116573: FreeSWITCH mod_sofia: stack buffer overflow from an over-long SIP To-header user

Vulnerability summary

CVE-2026-116573 is a medium (CVSS 6.5) Stack-based Buffer Overflow vulnerability in signalwire freeswitch. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Timeline

1. 05-11-2026
   PublishedVulnerability first disclosed.
2. 05-11-2026
   Last modifiedVulnerability information updated.

Description

FreeSWITCH is an open-source software telecommunications platform. From 1.10.0 until 1.11.1, a stack-based buffer overflow in  mod_sofia  when generating dialog-event notifications. A peer can establish a dialog with an excessively long SIP To-header user part and subsequently subscribe to that entity’s dialog events, causing the stored value to overflow a fixed-size stack buffer. Exploitation requires presence or shared-appearance management to be enabled and normally requires valid profile credentials, unless subscription authentication is disabled. The overflow can terminate the FreeSWITCH process and all active calls. This vulnerability is fixed in version 1.11.2.

• CWE-121Stack-based Buffer OverflowThe product writes past the end of a buffer that was allocated on the stack.
• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.