CVE-2026-49842 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, mod_verto's WebSocket frame loop intercepts a #-prefixed speed-test protocol (#SPU / #SPB / #SPE) before any authentication check. The declared payload size in #SPU was parsed with atoi() and only rejected non-positive values, so an unauthenticated peer could request up to INT_MAX bytes. The server then wrote roughly size * 10 bytes back during the download phase, on the order of 20 GB per request, yielding strong outbound bandwidth amplification from a short request. This issue has been patched in version 1.11.1.
A pre-authentication bandwidth amplification vulnerability has been identified in FreeSWITCH versions prior to 1.11.1, specifically within the mod_verto module's WebSocket frame loop. The issue arises because the WebSocket listener intercepts a speed-test protocol before any authentication is performed. An unauthenticated peer can exploit this by sending a request that specifies a payload size of up to INT_MAX bytes. The server then responds by sending back approximately ten times the requested size, effectively amplifying outbound bandwidth usage. This exploitation can lead to significant disruption, saturating network capacity and exhausting server resources.
Users are advised to upgrade to FreeSWITCH version 1.11.1 or later. If the mod_verto module is not in use, it can be disabled. For deployments that require mod_verto, consider restricting the WebSocket listener to trusted networks or using a firewall to control access.
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-p3gx-p2w7-wp35 | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-400 | Uncontrolled Resource Consumption | [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] |