CVE-2026-46539Network attack vector

Block-header forgery via empty-hop proof acceptance

Published Jun 9, 2026 · Updated Jun 9, 2026

Proof-verification bypass in Nimiq core-rs-albatross before 1.4.0 lets attackers forge proven block headers via inclusion proofs. BlockInclusionProof::is_block_proven treats an empty list from get_interlink_hops as success instead of confirming that the election head references the target block by hash. Exploitation requires a crafted proof for the election block immediately before the election head's epoch, and acceptance grants integrity over the asserted MacroBlock header without signature or hash verification.

CVSS severity5.9
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Proof-verification bypass in Nimiq core-rs-albatross before 1.4.0 lets attackers forge proven block headers via inclusion proofs. BlockInclusionProof::is_block_proven treats an empty list from get_interlink_hops as success instead of confirming that the election head references the target block by hash. Exploitation requires a crafted proof for the election block immediately before the election head's epoch, and acceptance grants integrity over the asserted MacroBlock header without signature or hash verification.

The record

CVE
CVE-2026-46539
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Nimiq
Product
core-rs-albatross
Classifications
CWE-345, T1565
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

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

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-345Insufficient Verification of Data Authenticity
T1565Data Manipulation

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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