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CVE-2026-49847

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

Published: Jun 9, 2026Updated: Jun 10, 2026 Sources: CVE List NVDCWE-674
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 67.1%
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, 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.

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-674

Affected Products

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

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/releases/tag/v1.11.1
github.com
https://github.com/signalwire/freeswitch/security/advisories/GHSA-2v74-pcgh-75wg
github.com

Timeline

Published
Jun 9, 2026
Last Updated
Jun 10, 2026

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