CVE-2026-49866 | libp2p is a JavaScript Implementation of libp2p networking s… | CVSS 7.5 HIGH

Description

libp2p is a JavaScript Implementation of libp2p networking stack. Prior to 16.0.0, @libp2p/gossipsub defaultDecodeRpcLimits set maxIhaveMessageIDs and maxIwantMessageIDs to Infinity, allowing oversized IHAVE and IWANT control message arrays in message/decodeRpc.ts and gossipsub.ts to synchronously iterate roughly 180,000 message IDs per 4 MB frame and block the Node.js event loop. This issue is fixed in version 16.0.0.

Metadata

CVE ID: CVE-2026-49866
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-06-01 22:03 UTC
Published: 2026-07-08 20:47 UTC
Last updated: 2026-07-09 14:40 UTC
Primary CWE: CWE-770
CWE-770: Allocation of Resources Without Limits or Throttlin…
Vendor / Product: libp2p / js-libp2p
Sources: cve.org · NVD

Severity & Metrics

7.5 HIGH CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
libp2p	js-libp2p	—	< 16.0.0

Weakness (CWE)

CWE	Source	Description
CWE-770	cna	CWE-770: Allocation of Resources Without Limits or Throttling

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.5	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (4)

https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv
https://github.com/libp2p/js-libp2p/pull/3520 https://github.com/libp2p/js-libp2p/pull/3520
https://github.com/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899 https://github.com/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899
https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0 https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0