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Medium · 5.3 CVE-2026-49843 EUVD-2026-35492

FreeSWITCH: Pre-authentication session eviction via attacker-chosen `sessid` in `mod_verto`

Published Jun 9, 2026 · Updated Jun 10, 2026 · Assigned by GitHub_M

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 JSON-RPC handler bound the connection to the client-supplied sessid on the first frame, before the authentication gate. Binding inserts the connection into the global session hash and, on a key collision, drops the prior occupant of that slot — sending it a verto.punt, detaching its calls, and closing its socket. An unauthenticated network attacker who knows a target session UUID could therefore evict the legitimate client. This issue has been patched in version 1.11.1.

Affected products

VendorProductAffectedFixed
signalwire freeswitch < 1.11.1 —

References