CVE-2026-49847 Details
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 1.11.1, 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.
A stack overflow vulnerability has been identified in FreeSWITCH versions prior to 1.11.1. The issue arises in the bundled cJSON parser, which processes deeply nested JSON documents. An unauthenticated WebSocket frame containing such a document can crash the FreeSWITCH process, leading to a denial of service by terminating all active calls and sessions. The vulnerability is present in any deployment with a reachable 'mod_verto' WebSocket listener, before authentication is performed.
Users are advised to upgrade to FreeSWITCH version 1.11.1 or later, where this vulnerability has been patched. Instructions for upgrading can be found in the FreeSWITCH release notes.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 9, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/signalwire/freeswitch/releases/tag/v1.11.1 | [email protected] | Release Notes |
| https://github.com/signalwire/freeswitch/security/advisories/GHSA-2v74-pcgh-75wg | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-674 | Uncontrolled Recursion | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| freeswitch freeswitch | < 1.11.1 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 10, 2026 | Initial Analysis | [email protected] |
| Jun 9, 2026 | New CVE Received | [email protected] |