CVE-2026-49843: FreeSWITCH: Pre-authentication session eviction via attacker-chosen `sessid` in `mod_verto`

Published Jun 9, 2026
·
Updated

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

2 affected components
FreeSWITCH FreeSWITCH mod_verto<1.11.1
FreeSWITCH FreeSWITCH<1.11.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade FreeSWITCH (mod_verto) to a version that resolves this vulnerability.

    Fixed in 1.11.1

Event History

Jun 9, 2026
CVE Published
via MITRE·04:04 PM
Data Sourced
via MITRE·04:04 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·05:17 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-49843?

The severity of CVE-2026-49843 is rated as medium with a score of 5.3.

2

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.

3

How can I fix CVE-2026-49843?

To fix CVE-2026-49843, upgrade FreeSWITCH to version 1.11.1 or later.

4

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.

5

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.

Contact

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