TI-2026-36751 Aliases CVE-2026-49847

FreeSWITCH: Stack overflow in bundled cJSON parser via deeply nested JSON

LOW 39CWE-674Published 2026-06-09 · Updated 2026-06-09

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-674.

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 version 1.11.1, a single unauthenticated WebSocket frame containing a deeply nested JSON document crashes the FreeSWITCH process via stack overflow, terminating all calls and sessions on the host. The recursion drives the worker thread's stack pointer into the stack guard page, raising SIGSEGV from the kernel before any usable write primitive develops. This issue has been patched in version 1.11.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00414 35th percentileScored 2026-11-07

Fix Fixed freeswitch (signalwire): 1.11.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
signalwire	freeswitch	before 1.11.1	1.11.1	Patch available	CNA

freeswitch Vendorsignalwire Affected before 1.11.1 Fixed in 1.11.1 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:freeswitch:freeswitch::::::::	before 1.11.1	Vulnerable	freeswitch

cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:* Versions before 1.11.1 Vulnerable ·freeswitch

Remediation

Fix · CNA freeswitch (signalwire) Fixed in 1.11.1

Timeline

2026-10-02 Threatist record created from CVE-2026-49847
2026-10-25 Priority changed: MEDIUM → LOW

References

Advisory 1

https://github.com/signalwire/freeswitch/security/advisories/GHSA-2v74-pcgh-75wg

Other 1

https://github.com/signalwire/freeswitch/releases/tag/v1.11.1

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

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