Buffer overflow in Signalwire Freeswitch
CVE-2026-116567
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Signalwire Freeswitch — versions < 1.11.2
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-116567?
- CVE-2026-116567 is a high-severity vulnerability in Signalwire Freeswitch, classified under Stack-based Buffer Overflow. CVSS score: 7.5/10. Published 2026-11-05.
- How severe is CVE-2026-116567?
- High severity. CVSS v3 base score is 7.5 out of 10.