Nimiq light-blockchain: Light blockchain rebranch issue_CVE-2026-46540

{
    "lastseen": "",
    "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": "2026-06-09T23:45:01.847Z",
    "modified": "2026-06-09T23:45:01.847Z",
    "type": "cve",
    "title": "Nimiq light-blockchain: Light blockchain rebranch issue",
    "source": "GitHub_M",
    "references": "https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-m3pg-qc2q-mg8c\nhttps://github.com/nimiq/core-rs-albatross/pull/3706\nhttps://github.com/nimiq/core-rs-albatross/releases/tag/v1.4.0",
    "id": "CVE-2026-46540",
    "bulletinFamily": "",
    "cwe": [
        "CWE-841"
    ],
    "cvelist": null,
    "sourceData": "nimiq core-rs-albatross < 1.4.0",
    "sourceHref": "",
    "cvss": {
        "score": 6.5,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "core-rs-albatross",
    "version": "< 1.4.0",
    "vendor": "nimiq",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}