---
id: CVE-2026-116783
title: 'FreeSWITCH mod_spandsp: out-of-bounds write parsing UDPTL error-recovery data'
summary: >-
  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-control…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'
cvssSource: cna
cwe:
  - CWE-129
  - CWE-787
vendor: signalwire
product: freeswitch
affected:
  - freeswitch < 1.11.2
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:41:44.761Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-116783'
references:
  - url: >-
      https://github.com/signalwire/freeswitch/security/advisories/GHSA-mjp3-3cq2-hxj4
    label: >-
      https://github.com/signalwire/freeswitch/security/advisories/GHSA-mjp3-3cq2-hxj4
  - url: >-
      https://github.com/signalwire/freeswitch/commit/b999d2a594f025ac0dd4d7b137635308ef298272
    label: >-
      https://github.com/signalwire/freeswitch/commit/b999d2a594f025ac0dd4d7b137635308ef298272
  - url: 'https://github.com/signalwire/freeswitch/releases/tag/v1.11.2'
    label: 'https://github.com/signalwire/freeswitch/releases/tag/v1.11.2'
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.557Z'
---

## Overview

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.

## Affected

- `freeswitch < 1.11.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.