CVE-2026-49842 — FreeSWITCH: Pre-authentication bandwidth amplification via `mod_verto` speed-test frames
FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hard…
Published: 2026-06-09 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7