SignalWire FreeSWITCH up to 1.11.1 mod_spandsp udptl_rx_packet memory corruption

Summaryinfo

A vulnerability was found in SignalWire FreeSWITCH up to 1.11.1 and classified as critical. This impacts the function udptl_rx_packet of the component mod_spandsp. Executing a manipulation can lead to memory corruption. This vulnerability appears as CVE-2026-116783. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in SignalWire FreeSWITCH up to 1.11.1. It has been declared as critical. This vulnerability affects the function udptl_rx_packet of the component mod_spandsp. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. As an impact it is known to affect integrity, and 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 1.11.2, udptl_rx_packet() used a peer-controlled FEC entry count directly to fill five-entry FEC arrays in a mod_spandsp T.38 session. A larger count wrote sender-controlled error-recovery data beyond those arrays and persisted the oversized count for a later reconstruction pass. Any peer able to deliver UDPTL to an established T.38 fax session can reach the parser, including deployments using fax applications or a T.38 gateway. The memory corruption can crash FreeSWITCH and end every active call, although remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.

The advisory is available at github.com. This vulnerability was named CVE-2026-116783 since 10/26/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 1.11.2 eliminates this vulnerability.

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Productinfo

Vendor

• SignalWire

Name

• FreeSWITCH

Version

• 1.11.0
• 1.11.1

Website

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

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