{"cve":"CVE-2026-52737","nvd":{"published":"2026-08-18T20:17:17.750","modified":"2026-09-09T21:13:25.910","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-345"],"references":["https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd","https://github.com/ZcashFoundation/zebra/commit/bc64dfe45746a86d14546a0a5a766387dd5a2942","https://github.com/ZcashFoundation/zebra/pull/10647","https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0","https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-gvjc-3w7c-92jx"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:10.689564601+00:00"},"epss":{"cve":"CVE-2026-52737","score":0.00262,"percentile":0.18088,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-gvjc-3w7c-92jx","url":"https://osv.dev/vulnerability/GHSA-gvjc-3w7c-92jx","summary":"Zebra has sync restart poisoning from single unauthenticated peer via above-lookahead block","modified":"2026-07-02T20:11:29.864832Z","packages":[{"ecosystem":"crates.io","name":"zebra-consensus","purl":"pkg:cargo/zebra-consensus","ranges":["<7.0.0"],"fixed":["7.0.0"]},{"ecosystem":"crates.io","name":"zebrad","purl":"pkg:cargo/zebrad","ranges":["<4.5.0"],"fixed":["4.5.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}