CVE-2026-103936 libp2p: Single pre-auth STUN packet terminates `@libp2p/webrtc` WebRTC-direct Node.js listeners
A remote attacker can crash the libp2p WebRTC listener by sending a single malformed STUN packet, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-103936?
CVE-2026-103936 is a high-severity denial of service vulnerability in @libp2p js-libp2p, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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 invalid_argument 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.
Which versions are affected by CVE-2026-103936?
How do I fix CVE-2026-103936?
No fix has been published for CVE-2026-103936 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-103936 being exploited?
There is no known exploitation of CVE-2026-103936 in the wild and no public exploit code.
Sources
Also known as GHSA-x3m2-6mg8-vj7f.