CVE-2026-116567
FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling
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.
Fixes and workarounds
Fix
FreeSWITCH (c): GitHub reports patched versions >= 1.11.2. Check the advisory for the affected release branch.
Source: GitHub GHSA-hj6x-9653-p796Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| freeswitch signalwire |
< 1.11.2 (affected) | CNA: GitHub_M |
FreeSWITCHFreeSWITCH
c |
<= 1.11.1 (affected, GitHub advisory range) | GitHub GHSA-hj6x-9653-p796 |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: GitHub_M |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41851b13c6CNA: GitHub_M · x_refsource_MISC
- https://github.com/signalwire/freeswitch/releases/tag/v1.11.2CNA: GitHub_M · x_refsource_MISC
- https://github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41851b13c6[email protected]
- https://github.com/signalwire/freeswitch/releases/tag/v1.11.2[email protected]
- https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796[email protected]
- https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796GitHub Security Advisories · advisory
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.