High 7.5Published Sep 17, 2026

CVE-2026-86040libp2p: Unbounded RPC decode + synchronous subscription processing in @libp2p/floodsub allows unauthenticated DoS

Updated under an hour ago (2026-10-19 06:30 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for libp2p js-libp2p

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-401, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Sep 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

libp2p js-libp2p libp2p:js_libp2p (from the name)	before 11.0.26	CNA record
@libp2p floodsub libp2p:floodsub (from the name)	before 11.0.26	CNA record

References

https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cvfg-hcf3-ggwvx-refsource-confirm
https://github.com/libp2p/js-libp2p/pull/3568x-refsource-misc
https://github.com/libp2p/js-libp2p/commit/fb9e8a76e9ac75924928fae4ce11d00f68320a83x-refsource-misc
https://github.com/libp2p/js-libp2p/releases/tag/floodsub-v11.0.26x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.