CVE-2026-46540Network attack vector

Light-client stall via incomplete macro-block rebranch

Published Jun 9, 2026 · Updated Jun 9, 2026

Improper workflow enforcement in Nimiq core-rs-albatross before 1.4.0 allows remote attackers to stall light-client chain progression. LightBlockchain::rebranch() updates only head after adopting a macro-block fork, leaving macro and validator state stale and validating later blocks against the wrong predecessor. Exploitation requires a fork rebranch whose tip is a macro block; an election-block tip causes every subsequent block to fail validator checks.

CVSS severity6.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper workflow enforcement in Nimiq core-rs-albatross before 1.4.0 allows remote attackers to stall light-client chain progression. LightBlockchain::rebranch() updates only head after adopting a macro-block fork, leaving macro and validator state stale and validating later blocks against the wrong predecessor. Exploitation requires a fork rebranch whose tip is a macro block; an election-block tip causes every subsequent block to fail validator checks.

The record

CVE
CVE-2026-46540
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Nimiq
Product
core-rs-albatross
Classifications
CWE-841, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 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=< 1.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nimiq · core-rs-albatrossversion=< 1.4.0

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

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.

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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-841Improper Enforcement of Behavioral Workflow
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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