Stack-based buffer overflow in Janus WebRTC Server - #VU155751
Published: October 14, 2026
Vulnerability identifier: #VU155751
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a persistent denial of service.
The vulnerability exists due to a stack-based buffer overflow in the Record&Play plugin's recording header parsers when reading .mjr info headers using unchecked file-supplied lengths. A remote attacker can record a session with an excessively long video a=fmtp attribute in its SDP offer, producing a recording whose header exceeds the 1500-byte stack buffer, to cause a persistent denial of service.
The oversized header is parsed during playback and server startup. On hardened builds, runtime overflow checks abort the process; the recording and its index remain on disk and are parsed again on subsequent startups.
Affected software
Janus WebRTC Server
Remediation
Install security update from vendor's website.
Janus WebRTC Server - addressed in versions 0.16.3, 1.4.3