# CVE-2026-116568: FreeSWITCH H.264 NAL unit buffer overread in mod_rtmp

Source: https://junglewise.ai/threats/cve-2026-116568-freeswitch-is-a-software-defined-telecom-stack-enabling-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-05  
License: CC BY 4.0 with a link back

CVE-2026-116568 · Severity: high · CVSS 7.5 · Published 2026-11-05

FreeSWITCH is a software-based telecom platform that processes voice and video calls. The mod_rtmp module handling video stream parsing contains a flaw where incoming H.264 video data with malformed length fields can cause the parser to read beyond its buffer, crashing the entire FreeSWITCH process and disconnecting all active calls. An attacker with network access to the RTMP port can trigger this denial of service remotely, though in some configurations authentication is required.

Technologies: [SignalWire FreeSWITCH](https://junglewise.ai/threats/technologies/freeswitch). Vendors: [SignalWire](https://junglewise.ai/threats/vendors/signalwire).

## Quick answers

**Is CVE-2026-116568 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116568 being exploited in the wild.

**How severe is CVE-2026-116568?** High severity, with a CVSS score of 7.5, published 5 November 2026.

**Which products and versions are affected?** SignalWire FreeSWITCH before 1.11.2.

**Is there a fix for CVE-2026-116568?** Yes: fixed in 1.11.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116568 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-116568?** Check whether you run SignalWire FreeSWITCH at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.11.2

## Technical details

The rtmp_rtmp2rtpH264() function in mod_rtmp parses inbound RTMP H.264 NAL units but fails to validate declared payload lengths against available buffer bytes. When a NAL unit specifies a size larger than remaining payload, the unsigned byte counter underflows, causing the parser to advance beyond the buffer boundary and crash on the next length-prefix read. The vulnerability requires RTMP connectivity on TCP port 1935 and, depending on configuration, may require directory authentication with valid credentials.

## Affected products

- SignalWire FreeSWITCH before 1.11.2

## Timeline

- 2026-11-05: advisory

## References

- [https://github.com/signalwire/freeswitch/commit/72cda5bfad67d14d8dbe76b8f8bdd38c4fa5c932](https://github.com/signalwire/freeswitch/commit/72cda5bfad67d14d8dbe76b8f8bdd38c4fa5c932)
- [https://github.com/signalwire/freeswitch/releases/tag/v1.11.2](https://github.com/signalwire/freeswitch/releases/tag/v1.11.2)

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