FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-116567
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-05 20:17:43 UTC
Updated2026-11-09 19:16:42 UTC
DescriptionFreeSWITCH 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.004320000 probability, percentile 0.376740000 (date 2026-11-09)

Problem Types: CWE-121 | CWE-121 CWE-121: Stack-based Buffer Overflow

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Signalwire Freeswitch affected < 1.11.2 Not specified

References

ReferenceSourceLinkTags
github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41... [email protected] github.com
github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796 [email protected] github.com
github.com/signalwire/freeswitch/releases/tag/v1.11.2 [email protected] github.com
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