Description
Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.4.0, when LightBlockchain::rebranch() adopts a fork chain whose tip is a macro block (checkpoint or election), it only updates self.head but fails to update self.macro_head, self.election_head, self.current_validators, or store the election header in the chain_store. This is in direct contrast with the full Blockchain::rebranch() at blockchain/src/blockchain/push.rs:504-518, which correctly updates all macro/election state when the new head is a macro block. After a rebranch to a macro block, the stale macro_head causes subsequent macro blocks pushed via push() to be verified against the wrong predecessor via verify_macro_successor(&this.macro_head). If the rebranch target was an election block, the stale current_validators causes every subsequent block to fail verify_validators(), completely stalling the light client's chain progression. This issue has been patched in version 1.4.0.
Published: 2026-06-09
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Wed, 10 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 10 Jun 2026 02:30:00 +0000

Type Values Removed Values Added
First Time appeared Nimiq
Nimiq core-rs-albatross
Vendors & Products Nimiq
Nimiq core-rs-albatross

Wed, 10 Jun 2026 00:00:00 +0000

Type Values Removed Values Added
Description Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.4.0, when LightBlockchain::rebranch() adopts a fork chain whose tip is a macro block (checkpoint or election), it only updates self.head but fails to update self.macro_head, self.election_head, self.current_validators, or store the election header in the chain_store. This is in direct contrast with the full Blockchain::rebranch() at blockchain/src/blockchain/push.rs:504-518, which correctly updates all macro/election state when the new head is a macro block. After a rebranch to a macro block, the stale macro_head causes subsequent macro blocks pushed via push() to be verified against the wrong predecessor via verify_macro_successor(&this.macro_head). If the rebranch target was an election block, the stale current_validators causes every subsequent block to fail verify_validators(), completely stalling the light client's chain progression. This issue has been patched in version 1.4.0.
Title Nimiq light-blockchain: Light blockchain rebranch issue
Weaknesses CWE-841
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'}


Subscriptions

Nimiq Core-rs-albatross
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-10T13:00:12.382Z

Reserved: 2026-05-14T20:42:31.368Z

Link: CVE-2026-46540

cve-icon Vulnrichment

Updated: 2026-06-10T13:00:03.367Z

cve-icon NVD

Status : Deferred

Published: 2026-06-10T00:16:54.230

Modified: 2026-06-10T19:37:41.437

Link: CVE-2026-46540

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-10T02:45:15Z

Weaknesses