libp2p is a JavaScript implementation of the libp2p networking stack. From 15.0.0 until 16.0.5, @libp2p/gossipsub uses the default StrictSign policy in packages/gossipsub/src/utils/buildRawMessage.ts, where validateToRawMessage verifies a signature with attacker-controlled msg.key but skips binding that key to msg.from when the claimed author is an RSA peer ID that does not inline a public key. An unauthenticated attacker can place a victim RSA peer ID in msg.from, sign the message with the attacker's private key, and supply the attacker's public key in msg.key, causing the message to be accepted and propagated as authored by the victim. Applications that trust message.from for validators, authorization, accounting, moderation, reputation, or audit logging can process attacker-controlled data under false origin attribution. The issue is fixed in version 16.0.5.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-c3gv-825q-fvmp libp2p: Gossipsub StrictSign accepts attacker-signed messages as a victim RSA peer ID
Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Thu, 17 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 17 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Description libp2p is a JavaScript implementation of the libp2p networking stack. From 15.0.0 until 16.0.5, @libp2p/gossipsub uses the default StrictSign policy in packages/gossipsub/src/utils/buildRawMessage.ts, where validateToRawMessage verifies a signature with attacker-controlled msg.key but skips binding that key to msg.from when the claimed author is an RSA peer ID that does not inline a public key. An unauthenticated attacker can place a victim RSA peer ID in msg.from, sign the message with the attacker's private key, and supply the attacker's public key in msg.key, causing the message to be accepted and propagated as authored by the victim. Applications that trust message.from for validators, authorization, accounting, moderation, reputation, or audit logging can process attacker-controlled data under false origin attribution. The issue is fixed in version 16.0.5.
Title libp2p: Gossipsub StrictSign accepts attacker-signed messages as a victim RSA peer ID
Weaknesses CWE-345
CWE-347
References
Metrics cvssV3_1

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


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-17T17:24:35.905Z

Reserved: 2026-09-04T19:29:21.057Z

Link: CVE-2026-86038

cve-icon Vulnrichment

Updated: 2026-09-17T17:24:29.895Z

cve-icon NVD

Status : Received

Published: 2026-09-17T16:18:16.927

Modified: 2026-09-17T18:17:12.203

Link: CVE-2026-86038

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses