CVE-2026-86038
Received Received - Intake

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Vulnerability report for CVE-2026-86038, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-17

Last updated on: 2026-09-17

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-17
Last Modified
2026-09-17
Generated
2026-09-20
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-345 The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.

Attack-Flow Graph

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