{"id":"CVE-2026-52732","sourceIdentifier":"security-advisories@github.com","published":"2026-08-18T20:17:16.710","lastModified":"2026-10-22T22:10:00.250","vulnStatus":"Deferred","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'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."},{"lang":"es","value":"ZEBRA es un nodo Zcash escrito completamente en Rust. Antes de la versión 4.5.0, un par P2P no autenticado puede monopolizar las 25 ranuras MAX_INBOUND_CONCURRENCY en la tubería de descarga y verificación de la mempool entrante de Zebra. En zebrad/src/components/mempool/downloads.rs, la cola limitada se compartía globalmente sin contabilidad por par, mientras que la identidad del par no se transmitía a través de Gossip y las respuestas FullQueue se mapeaban a Response::Nil en lugar de alcanzar el manejo de desconexión por sobrecarga. Un atacante puede anunciar identificadores de transacción falsos y permanecer en silencio para que cada tarea retenga una ranura hasta TRANSACTION_DOWNLOAD_TIMEOUT, luego rellenar periódicamente la cola a medida que las ranuras expiran. Mientras está saturado, las transacciones de pares honestos y las solicitudes locales de sendrawtransaction son rechazadas con MempoolError::FullQueue, aunque la validación y sincronización de bloques continúan. Este problema está solucionado en la versión 4.5.0."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"ZcashFoundation","product":"zebra","versions":[{"version":"< 4.5.0","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","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":"2026-08-18T19:32:12.651849Z","id":"CVE-2026-52732","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Primary","description":[{"lang":"en","value":"CWE-770"}]}],"references":[{"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":"security-advisories@github.com"},{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}