CVE-2026-103936: libp2p: Single pre-auth STUN packet terminates `@libp2p/webrtc` WebRTC-direct Node.js listeners
libp2p is a JavaScript implementation of the libp2p networking stack. Prior to 6.0.28, the @libp2p/webrtc webRTCDirect() Node.js listener processes unauthenticated STUN Binding Requests before PeerId authentication, Noise, muxing, protocol negotiation, connection creation, or connection-manager admission. The listener in packages/transport-webrtc/src/private-to-public/utils/stun-listener.ts forwards the packet-controlled request.ufrag into DirectRTCPeerConnection.setLocalDescription, where the value is reused as an ICE password without validating its required length and character set. A short credential causes node-datachannel or libdatachannel to raise an uncaught native invalidargument and abort the process with SIGABRT, allowing a single remote UDP packet to deny service. The confirmed impact is process termination only, with no demonstrated memory corruption, code execution, browser impact, confidentiality impact, integrity impact, or connection-limit bypass. This issue is fixed in version 6.0.28.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
@libp2p/webrtcto a version that resolves this vulnerability.Fixed in 6.0.28
Event History
Frequently Asked Questions
Which deployments are exposed to this denial of service?
Node.js deployments using the @libp2p/webrtc webRTCDirect() listener are affected before version 6.0.28. Browser impact has not been demonstrated.
Does an attacker need to authenticate or establish a libp2p connection first?
No. A remote attacker can trigger the issue with a single unauthenticated UDP STUN Binding Request, before PeerId authentication, Noise, muxing, protocol negotiation, connection creation, or connection-manager admission.
What is the practical impact of successful exploitation?
The Node.js process aborts with SIGABRT, causing a denial of service. The confirmed impact is limited to process termination; memory corruption, code execution, confidentiality or integrity impact, and connection-limit bypass have not been demonstrated.
What version fixes the issue?
Upgrade @libp2p/webrtc to version 6.0.28 or later.