signalwire FreeSWITCH up to 1.11.0 WebSocket Frame atoi resource consumption

Summaryinfo

A vulnerability categorized as problematic has been discovered in signalwire FreeSWITCH up to 1.11.0. This affects the function atoi of the component WebSocket Frame Handler. The manipulation results in resource consumption. This vulnerability was named CVE-2026-49842. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in signalwire FreeSWITCH up to 1.11.0. It has been classified as problematic. Affected is the function atoi of the component WebSocket Frame Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-49842 since 06/01/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 1.11.1 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Vendor

• signalwire

Name

• FreeSWITCH

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11.0

Website

• Product: https://github.com/signalwire/freeswitch/

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