CVE-2026-86040

High CVSS 7.5

Published 2026-09-17 · last changed 2026-09-17

The fix

We hold no Microsoft remediation data for CVE-2026-86040, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

libp2p is a JavaScript implementation of the libp2p networking stack. Prior to 11.0.26, @libp2p/floodsub accepts unauthenticated RPC frames on /floodsub/1.0.0 through PeerStreams.attachInboundStream in packages/floodsub/src/peer-streams.ts without protobuf element limits, then processRpc and processRpcSubOpt in packages/floodsub/src/floodsub.ts synchronously process the subscriptions array without a per-frame cap. A single bounded-size frame can decode into millions of empty subscription entries that block the event loop, while hundreds of thousands of unique-topic SUBSCRIBE entries allocate PeerSet objects in this.topics that are not removed after peer removal or stop. Empty entries cause CPU exhaustion but do not grow this.topics; persistent memory growth requires unique topics. The subscription path bypasses message signature validation and the message-only processing queue, allowing a remote peer to cause sustained CPU denial of service, memory exhaustion, out-of-memory termination, and node unavailability. The issue is fixed in version 11.0.26.

Sources

NVD record for CVE-2026-86040

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H