CVE-2026-49866

libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays

Published Jul 8, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-cwc9-cp4j-mcvv libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays
History
Type Values Removed Values Added
First Time appeared Libp2p
Libp2p libp2p
Vendors & Products Libp2p
Libp2p libp2p
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 9, 2026, 2:40 PM
Reserved
Jun 1, 2026, 10:03 PM
Status
Deferred
Published
Jul 8, 2026, 9:16 PM
Modified
Oct 25, 2026, 5:10 PM