FKIE_CVE-2026-52732

Vulnerability from fkie_nvd - Published: 2026-08-18 20:17 - Updated: 2026-10-22 22:10
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Summary
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, one unauthenticated P2P peer can monopolize all 25 MAX_INBOUND_CONCURRENCY slots in Zebra's inbound mempool download and verification pipeline. In zebrad/src/components/mempool/downloads.rs, the bounded queue was shared globally without per-peer accounting, while peer identity was not carried through Gossip and FullQueue responses were mapped to Response::Nil instead of reaching overload disconnection handling. An attacker can advertise fake transaction identifiers and remain silent so each task holds a slot until TRANSACTION_DOWNLOAD_TIMEOUT, then periodically refill the queue as slots expire. While saturated, honest peer transactions and local sendrawtransaction requests are rejected with MempoolError::FullQueue, although block validation and synchronization continue. This issue is fixed in version 4.5.0.
References
security-advisories@github.comhttps://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd
security-advisories@github.comhttps://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0
security-advisories@github.comhttps://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "zebra",
          "vendor": "ZcashFoundation",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.5.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, one unauthenticated P2P peer can monopolize all 25 MAX_INBOUND_CONCURRENCY slots in Zebra\u0027s inbound mempool download and verification pipeline. In zebrad/src/components/mempool/downloads.rs, the bounded queue was shared globally without per-peer accounting, while peer identity was not carried through Gossip and FullQueue responses were mapped to Response::Nil instead of reaching overload disconnection handling. An attacker can advertise fake transaction identifiers and remain silent so each task holds a slot until TRANSACTION_DOWNLOAD_TIMEOUT, then periodically refill the queue as slots expire. While saturated, honest peer transactions and local sendrawtransaction requests are rejected with MempoolError::FullQueue, although block validation and synchronization continue. This issue is fixed in version 4.5.0."
    },
    {
      "lang": "es",
      "value": "ZEBRA es un nodo Zcash escrito completamente en Rust. Antes de la versi\u00f3n 4.5.0, un par P2P no autenticado puede monopolizar las 25 ranuras MAX_INBOUND_CONCURRENCY en la tuber\u00eda de descarga y verificaci\u00f3n de la mempool entrante de Zebra. En zebrad/src/components/mempool/downloads.rs, la cola limitada se compart\u00eda globalmente sin contabilidad por par, mientras que la identidad del par no se transmit\u00eda a trav\u00e9s de Gossip y las respuestas FullQueue se mapeaban a Response::Nil en lugar de alcanzar el manejo de desconexi\u00f3n por sobrecarga. Un atacante puede anunciar identificadores de transacci\u00f3n falsos y permanecer en silencio para que cada tarea retenga una ranura hasta TRANSACTION_DOWNLOAD_TIMEOUT, luego rellenar peri\u00f3dicamente la cola a medida que las ranuras expiran. Mientras est\u00e1 saturado, las transacciones de pares honestos y las solicitudes locales de sendrawtransaction son rechazadas con MempoolError::FullQueue, aunque la validaci\u00f3n y sincronizaci\u00f3n de bloques contin\u00faan. Este problema est\u00e1 solucionado en la versi\u00f3n 4.5.0."
    }
  ],
  "id": "CVE-2026-52732",
  "lastModified": "2026-10-22T22:10:00.250",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-52732",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-18T19:32:12.651849Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-18T20:17:16.710",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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