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TI-2026-85611 Aliases CVE-2026-116567

Pre-authentication stack overflow in FreeSWITCH mod_rtmp

Priority LOW 33CWE-121Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

FreeSWITCH before 1.11.2 is affected in deployments that build and load its mod_rtmp module. The rtmp_handle_control() function renders an RTMP user-control message into a 200-byte stack buffer with an unbounded sprintf loop, a stack-based buffer overflow (CWE-121). An unauthenticated remote attacker can send one message of roughly 70 bytes or more before any RTMP login, crashing FreeSWITCH and ending every active call.

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, rtmp_handle_control() rendered an RTMP user-control message into a 200-byte stack buffer using an unbounded sprintf loop controlled by the wire message length. A body of roughly 70 bytes or more overflowed the stack before any RTMP login, because the handshake authenticates neither side. The flaw affects deployments that build and load mod_rtmp, which is disabled in the stock build and configuration but commonly exposes a listener on TCP port 1935 when enabled. One unauthenticated message can crash FreeSWITCH and end every active call; the constrained ASCII hex output has not yielded control-flow hijacking. This issue is fixed in version 1.11.2.

Why it matters now

EPSS 0.00432 37th 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 signalwire 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-2026-116567
  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