Use-after-free in Janus WebRTC Server - #VU155753
Published: October 14, 2026
Vulnerability identifier: #VU155753
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-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in the SIP plugin's helper-registration code in src/plugins/janus_sip.c when processing helper registrations referencing a freed master session. A remote attacker can convert a master session into a helper, detach its handle, and register another helper using the stale master identifier to cause a denial of service.
The SIP plugin is loaded by default. Guest registration sends no SIP messages to external servers.
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