CVE-2026-46540

{
  "id": "CVE-2026-46540",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-46540",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-10T12:59:40.645536Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 2.5,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "nimiq",
          "product": "core-rs-albatross",
          "versions": [
            {
              "status": "affected",
              "version": "< 1.4.0"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-06-10T00:16:54.230",
  "references": [
    {
      "url": "https://github.com/nimiq/core-rs-albatross/pull/3706",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nimiq/core-rs-albatross/releases/tag/v1.4.0",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-m3pg-qc2q-mg8c",
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-841"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "Nimiq es una implementación en Rust del protocolo Nimiq Proof-of-Stake basado en el algoritmo de consenso Albatross. Antes de la versión 1.4.0, cuando LightBlockchain::rebranch() adopta una cadena bifurcada cuya punta es un macrobloque (punto de control o elección), solo actualiza self.head pero no actualiza self.macro_head, self.election_head, self.current_validators, ni almacena el encabezado de la elección en el chain_store. Esto contrasta directamente con el Blockchain::rebranch() completo en blockchain/src/blockchain/push.rs:504-518, que actualiza correctamente todo el estado de macro/elección cuando el nuevo head es un macrobloque. Después de un rebranch a un macrobloque, el macro_head obsoleto causa que los macrobloques subsiguientes empujados a través de push() sean verificados contra el predecesor incorrecto a través de verify_macro_successor(&this.macro_head). Si el objetivo del rebranch era un bloque de elección, los current_validators obsoletos causan que cada bloque subsiguiente falle verify_validators(), deteniendo completamente la progresión de la cadena del cliente ligero. Este problema ha sido parcheado en la versión 1.4.0."
    }
  ],
  "lastModified": "2026-07-23T09:10:00.113",
  "sourceIdentifier": "security-advisories@github.com"
}