CVE-2026-49847 HIGH

CVE-2026-49847: FreeSWITCH: Stack overflow in bundled cJSON parser via deeply nested JSON

Vendor Signalwire
Product freeswitch
Weakness CWE-674
Published June 9, 2026
Last update June 9, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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 1.11.1, a single unauthenticated WebSocket frame containing a deeply nested JSON document crashes the FreeSWITCH process via stack overflow, terminating all calls and sessions on the host. The recursion drives the worker thread's stack pointer into the stack guard page, raising SIGSEGV from the kernel before any usable write primitive develops. This issue has been patched in version 1.11.1.

Key dates

02Disclosure timeline

June 9, 2026 CVE published
June 9, 2026 Record updated