{"id":"CVE-2026-116567","title":"FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling","summary":"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 RTM…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-121"],"vendor":"signalwire","product":"freeswitch","affected":["freeswitch < 1.11.2"],"published":"2026-11-05","updated":"2026-11-05","sourceUpdated":"2026-11-05T19:23:25.422Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-116567","references":[{"url":"https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796","label":"https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796"},{"url":"https://github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41851b13c6","label":"https://github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41851b13c6"},{"url":"https://github.com/signalwire/freeswitch/releases/tag/v1.11.2","label":"https://github.com/signalwire/freeswitch/releases/tag/v1.11.2"}],"tags":["cve.org"],"ingestedAt":"2026-11-05T22:38:31.532Z","slug":"CVE-2026-116567","body":"## Overview\n\nFreeSWITCH 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.\n\n## Affected\n\n- `freeswitch < 1.11.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}