{"id":"CVE-2026-52732","title":"ZEBRA is a Zcash node written entirely in Rust","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/memp…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-770"],"vendor":"zebrad","product":"zebrad","affected":["zebrad <= 4.4.1"],"patched":["zebrad 4.5.0"],"published":"2026-08-18","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:13:25.910","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-52732","references":[{"url":"https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd","label":"security-advisories@github.com"},{"url":"https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0","label":"security-advisories@github.com"},{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c","label":"security-advisories@github.com"},{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/ZcashFoundation/zebra/blob/d4cd662c716382f6397d2a730148025a1ca79fec/zebrad/src/components/mempool/downloads.rs#L82"},{"url":"https://github.com/advisories/GHSA-4fc2-h7jh-287c"}],"tags":["nvd","ghsa","rust"],"epss":0.00371,"epssPercentile":0.31026,"ecosystem":"rust","ingestedAt":"2026-07-02T19:41:50.908Z","slug":"CVE-2026-52732","body":"## Overview\n\nZEBRA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-52732)\n\nAffected packages:\n\n- `zebrad <= 4.4.1`\n\nPatched in:\n\n- `zebrad 4.5.0`\n\nSource: https://github.com/advisories/GHSA-4fc2-h7jh-287c","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}