CVE-2026-34063Network attack vector

Network outage via duplicate discovery substream

Published Apr 22, 2026 · Updated Apr 22, 2026

Reachable assertion in Nimiq network-libp2p before 1.3.0 allows remote attackers to crash node networking via a duplicate discovery substream. The discovery ConnectionHandler accepts a second inbound or outbound protocol substream on an existing connection and invokes a panic branch instead of rejecting the duplicate. Any unauthenticated network peer that negotiates the discovery protocol twice can terminate the swarm task, leaving peer-to-peer networking offline until the node restarts.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Nimiq network-libp2p before 1.3.0 allows remote attackers to crash node networking via a duplicate discovery substream. The discovery ConnectionHandler accepts a second inbound or outbound protocol substream on an existing connection and invokes a panic branch instead of rejecting the duplicate. Any unauthenticated network peer that negotiates the discovery protocol twice can terminate the swarm task, leaving peer-to-peer networking offline until the node restarts.

The record

CVE
CVE-2026-34063
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
Nimiq
Product
nimiq-network-libp2p
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nimiq · nimiq-network-libp2pversion=< 1.3.0

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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