libp2p up to 16.0.4 Gossipsub buildRawMessage.ts validateToRawMessage key/from improper authentication

CVSS Meta Temp Score
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CTI Interest Score
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6.3$0-$5k0.40

Summaryinfo

A vulnerability identified as problematic has been detected in libp2p up to 16.0.4. This affects the function validateToRawMessage of the file packages/gossipsub/src/utils/buildRawMessage.ts of the component Gossipsub. This manipulation of the argument key/from causes improper authentication. This vulnerability appears as CVE-2026-86038. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in libp2p up to 16.0.4. Affected by this vulnerability is the function validateToRawMessage of the file packages/gossipsub/src/utils/buildRawMessage.ts of the component Gossipsub. The manipulation of the argument key/from with an unknown input leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-86038 since 09/04/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Upgrading to version 16.0.5 eliminates this vulnerability.

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Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: libp2p 16.0.5

Timelineinfo

09/04/2026 CVE reserved
09/17/2026 +13 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-86038 (🔒)
GCVE (CVE): GCVE-0-2026-86038
GCVE (VulDB): GCVE-100-406513

Entryinfo

Created: 09/17/2026 17:49
Changes: 09/17/2026 17:49 (66)
Complete: 🔍
Cache ID: 216::103

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