CVE-2026-49843: FreeSWITCH: Pre-authentication session eviction via attacker-chosen `sessid` in `mod_verto`
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, modverto'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 Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
FreeSWITCH (mod_verto)to a version that resolves this vulnerability.Fixed in 1.11.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-49843?
The severity of CVE-2026-49843 is rated as medium with a score of 5.3.
What systems are affected by CVE-2026-49843?
CVE-2026-49843 affects FreeSWITCH versions prior to 1.11.1 that utilize the mod_verto module.
How can I fix CVE-2026-49843?
To fix CVE-2026-49843, upgrade FreeSWITCH to version 1.11.1 or later.
What type of vulnerability is CVE-2026-49843?
CVE-2026-49843 is a pre-authentication session eviction vulnerability that can be exploited via an attacker-chosen sessid.
What is the impact of exploiting CVE-2026-49843?
Exploiting CVE-2026-49843 may allow an attacker to disrupt ongoing sessions by evicting users based on custom session IDs.