Read the docs
TI-2026-85629 Aliases CVE-2026-116783

Out-of-bounds write in FreeSWITCH mod_spandsp UDPTL parsing

Priority LOW 37CWE-129Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

FreeSWITCH before 1.11.2 is affected in its mod_spandsp module. The udptl_rx_packet() function uses a peer-controlled forward error correction entry count to fill five-entry arrays, so a larger count writes past the arrays (CWE-787, CWE-129). Any peer able to send UDPTL data to an established T.38 fax session can trigger the flaw, which can crash FreeSWITCH and end every active call. Remote code execution has not been demonstrated.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

EPSS 0.00618 49th percentileScored 2026-11-07
Fix Fixed freeswitch (signalwire): 1.11.2

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
signalwirefreeswitchbefore 1.11.21.11.2Patch availableCNA
  • freeswitch Vendorsignalwire Affected before 1.11.2 Fixed in 1.11.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:*——freeswitch
  • cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:* Versions — — ·freeswitch

Remediation

Upgrade FreeSWITCH to version 1.11.2, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA freeswitch (signalwire) Fixed in 1.11.2

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-11-05 Threatist record created from CVE-2026-116783
  2. 2026-11-06 Affected versions changed · Red Hat
  3. 2026-11-06 CVSS score added · Red Hat
  4. 2026-11-07 Priority changed: MEDIUM → LOW

References

Other 3

  • TI-2023-08915 heap-over-flow in stun_parse_attribute in sofia-sip CVSS 3.1CRITICAL 9.8
  • TI-2022-13049 Heap-based Buffer Overflow and Out-of-bounds Write in Sofia-SIP CVSS 3.1CRITICAL 9.8
  • TI-2023-28097 FreeSWITCH susceptible to Denial of Service via DTLS Hello packets during call initiation CVSS 3.1HIGH 7.5
  • TI-2023-20909 Resource allocation without limits in signalwire freeswitch CVSS 3.1HIGH 7.5
  • TI-2023-20908 FreeSWITCH allows remote users to trigger out of bounds write by offering an ICE candidate with unknown component ID CVSS 3.1HIGH 7.5
  • TI-2023-15601 heap-over-flow and integer-overflow in sofia-sip CVSS 3.1HIGH 7.5
See all 44 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences