libp2p: Gossipsub StrictSign accepts attacker-signed messages as a victim RSA peer ID

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-86038
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 16:18:16 UTC
Updated2026-09-17 18:17:12 UTC
Descriptionlibp2p 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

Problem Types: CWE-345 | CWE-347 | CWE-345 CWE-345: Insufficient Verification of Data Authenticity | CWE-347 CWE-347: Improper Verification of Cryptographic Signature

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Libp2p Js-libp2p affected >= 15.0.0, < 16.0.5 Not specified

References

ReferenceSourceLinkTags
github.com/libp2p/js-libp2p/commit/cec2b1f349d130065e561349a0336a239528267f [email protected] github.com
github.com/libp2p/js-libp2p/pull/3569 [email protected] github.com
github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.5 [email protected] github.com
github.com/libp2p/js-libp2p/security/advisories/GHSA-c3gv-825q-fvmp 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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