TI-2026-36747 Aliases CVE-2026-49843

FreeSWITCH: Pre-authentication session eviction via attacker-chosen `sessid` in `mod_verto`

LOW 30CWE-287Published 2026-06-09 · Updated 2026-06-10

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: None · None · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.

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, mod_verto's JSON-RPC handler bound the connection to the client-supplied sessid on the first frame, before the authentication gate. Binding inserts the connection into the global session hash and, on a key collision, drops the prior occupant of that slot — sending it a verto.punt, detaching its calls, and closing its socket. An unauthenticated network attacker who knows a target session UUID could therefore evict the legitimate client. This issue has been patched in version 1.11.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00284 21st 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-2026-49843

References

Advisory 1

https://github.com/signalwire/freeswitch/security/advisories/GHSA-9457-fxr9-x78m

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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