---
id: CVE-2026-86040
title: libp2p is a JavaScript implementation of the libp2p networking stack
summary: >-
  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.…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-401
  - CWE-770
vendor: libp2p
product: js-libp2p
affected:
  - js-libp2p < 11.0.26
  - floodsub < 11.0.26
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T20:18:49.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86040'
references:
  - url: >-
      https://github.com/libp2p/js-libp2p/commit/fb9e8a76e9ac75924928fae4ce11d00f68320a83
    label: security-advisories@github.com
  - url: 'https://github.com/libp2p/js-libp2p/pull/3568'
    label: security-advisories@github.com
  - url: 'https://github.com/libp2p/js-libp2p/releases/tag/floodsub-v11.0.26'
    label: security-advisories@github.com
  - url: >-
      https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cvfg-hcf3-ggwv
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-17T17:06:11.592901Z'
ingestedAt: '2026-09-17T16:21:47.715Z'
epss: 0.00373
epssPercentile: 0.31039
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.