CVE-2026-116567

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

Published Nov 5, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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 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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Freeswitch
Freeswitch freeswitch
CPEs cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:*
Vendors & Products Freeswitch
Freeswitch freeswitch
Type Values Removed Values Added
First Time appeared Signalwire
Signalwire freeswitch
Vendors & Products Signalwire
Signalwire freeswitch
Type Values Removed Values Added
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 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.
Title FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling
Weaknesses CWE-121
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Nov 9, 2026, 6:21 PM
Reserved
Oct 26, 2026, 3:03 PM
Status
Analyzed
Published
Nov 5, 2026, 8:17 PM
Modified
Nov 10, 2026, 6:58 PM