CVE-2026-49842

HIGH

FreeSWITCH: Pre-authentication bandwidth amplification via `mod_verto` speed-test frames

Title source: cna
STIX 2.1

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.

References (2)

Core 2

Scores

CVSS v3 7.5
EPSS 0.0045
EPSS Percentile 35.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400
Status published
Products (2)
freeswitch/freeswitch < 1.11.1
signalwire/freeswitch < 1.11.1
Published Jun 09, 2026
Tracked Since Jun 09, 2026