CVE-2026-116568: FreeSWITCH: Out-of-bounds read in mod_rtmp H.264 video message parsing

Vulnerability summary

CVE-2026-116568 is a high (CVSS 7.5) Out-of-bounds Read vulnerability in signalwire freeswitch. EPSS estimates a 0.53% chance of exploitation in the next 30 days, higher than 44.9% of scored vulnerabilities.

Timeline

1. 05-11-2026
   PublishedVulnerability first disclosed.
2. 05-11-2026
   Last modifiedVulnerability information updated.

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.
• CWE-191Integer Underflow (Wrap or Wraparound)The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.