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CVE-2026-49842

FreeSWITCH: Pre-authentication bandwidth amplification via `mod_verto` speed-test frames

Published: Jun 9, 2026Updated: Jun 10, 2026 Sources: CVE List NVDCWE-400
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 64.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

Description

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 WebSocket frame loop intercepts a #-prefixed speed-test protocol (#SPU / #SPB / #SPE) before any authentication check. The declared payload size in #SPU was parsed with atoi() and only rejected non-positive values, so an unauthenticated peer could request up to INT_MAX bytes. The server then wrote roughly size * 10 bytes back during the download phase, on the order of 20 GB per request, yielding strong outbound bandwidth amplification from a short request. This issue has been patched in version 1.11.1.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-400

Affected Products

freeswitchsignalwire
Mixed
Communications / voip-telephony
freeswitchfreeswitch
On-prem
Communications / voip-telephony
signalwirecommercialCommunicationsaka freeswitch (related), sofia-sip (related)
freeswitchoss-projectCommunications

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/signalwire/freeswitch/security/advisories/GHSA-p3gx-p2w7-wp35
github.com
https://github.com/signalwire/freeswitch/releases/tag/v1.11.1
github.com

Timeline

Published
Jun 9, 2026
Last Updated
Jun 10, 2026

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