{"id":"CVE-2026-109366","aliases":[],"title":"Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"ZcashFoundation","name":"zebra","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"6.4.0","versionType":"semver"},{"version":"6.4.0","status":"unaffected","versionType":"semver"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-109366"}],"remediation":[],"description":"Zebra before 6.4.0 contains an improper integrity validation vulnerability in the inbound gossip download path that allows unauthenticated peers to force dropping of new blocks without penalty. Attackers can serve a real block with a coinbase scriptSig rewritten to height 1, which keeps the ZIP-244 block hash, triggering a behind-tip drop before consensus validation and delaying tip discovery for mining backends.","severity":"medium","score":6.3,"published":"2026-10-12T16:05:43.620Z","modified":"2026-10-26T20:37:40.885Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3","https://www.vulncheck.com/advisories/zebra-before-6.4.0-gossiped-block-drop-via-forged-coinbase-scriptsig-height"],"sources":[{"name":"CVE","id":"CVE-2026-109366","modified":"2026-10-26T20:37:40.885Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-109366"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","score":6.3},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","score":3.7}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T22:20:33.483Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}