Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M
CVE-2026-86040libp2p: Unbounded RPC decode + synchronous subscription processing in @libp2p/floodsub allows unauthenticated DoS
High 7.5
In plain English
A high-severity uncontrolled resource consumption in floodsub from @libp2p. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
Weakness: CWE-400, CWE-401, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cvfg-hcf3-ggwv x_refsource_CONFIRM
- https://github.com/libp2p/js-libp2p/pull/3568 x_refsource_MISC
- https://github.com/libp2p/js-libp2p/commit/fb9e8a76e9ac75924928fae4ce11d00f68320a83 x_refsource_MISC
- https://github.com/libp2p/js-libp2p/releases/tag/floodsub-v11.0.26 x_refsource_MISC