CVE-2026-52737

{
  "id": "CVE-2026-52737",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-18T20:17:17.750",
  "lastModified": "2026-11-09T20:10:00.200",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a malicious unauthenticated P2P peer can answer Zebra's outbound getblocks or FindBlocks request with a small two-hash inventory and then serve a syntactically valid block whose coinbase height is far above the local chain tip. In zebrad/src/components/sync/downloads.rs, BlockDownloadVerifyError::AboveLookaheadHeightLimit originally carried only the block height and hash, so handle_block_response could not attribute the failure to the advertising peer. The error then reached the restart-worthy default path in zebrad/src/components/sync.rs, cancelling all in-flight downloads from honest peers and imposing a 67-second sync restart delay on mainnet. Because the peer was neither scored nor disconnected, the peer could repeat the cycle indefinitely with minimal bandwidth and significantly degrade synchronization without corrupting state. This issue is fixed in version 4.5.0."
    },
    {
      "lang": "es",
      "value": "ZEBRA es un nodo de Zcash escrito completamente en Rust. Antes de la versión 4.5.0, un par P2P malicioso no autenticado podía responder a la solicitud saliente de Zebra de getblocks o FindBlocks con un pequeño inventario de dos hashes y luego servir un bloque sintácticamente válido cuya altura de coinbase estaba muy por encima de la punta de la cadena local. En zebrad/src/components/sync/downloads.rs, BlockDownloadVerifyError::AboveLookaheadHeightLimit originalmente solo contenía la altura y el hash del bloque, por lo que handle_block_response no podía atribuir el fallo al par anunciante. El error luego alcanzó la ruta predeterminada que amerita un reinicio en zebrad/src/components/sync.rs, cancelando todas las descargas en curso de pares honestos e imponiendo un retraso de 67 segundos en el reinicio de la sincronización en la red principal. Debido a que el par no fue puntuado ni desconectado, el par podía repetir el ciclo indefinidamente con un ancho de banda mínimo y degradar significativamente la sincronización sin corromper el estado. Este problema está solucionado en la versión 4.5.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "ZcashFoundation",
          "product": "zebra",
          "versions": [
            {
              "version": "< 4.5.0",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "ZcashFoundation",
          "product": "zebra-consensus",
          "versions": [
            {
              "version": "< 7.0.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-18T19:33:21.510952Z",
          "id": "CVE-2026-52737",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/ZcashFoundation/zebra/commit/bc64dfe45746a86d14546a0a5a766387dd5a2942",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/ZcashFoundation/zebra/pull/10647",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-gvjc-3w7c-92jx",
      "source": "[email protected]"
    }
  ]
}